ALBERT

Description: In this paper we present the geological evidence of paleotsunamis in the Augusta area together with some paleoseismological implication derived from the discovery of multiple inundation events. It is well known that eastern Sicily has been affected in historical time by large earthquakes (CPTI Working group, 2004) and its southern sector in particular was strongly hit by the 1693 and 1169 events that were followed by devastating tsunamis. The Augusta Bay area is one of the locations where the information available from historical reports on tsunami effects (hit localities, inundated areas and run-up distribution) stimulated our curiosity in searching for the geological signature of tsunamis. The research was carried out through a multi-theme approach consisting of historical studies, geomorphological and geological surveys, coring campaigns, laboratory analyses (paleontological, radiometric, SEM, X-Ray, susceptibility, tephra, etc.).

Description: Published

Description: Roma

Description: 3.2. Tettonica attiva

Description: open

Description: Foreland basins are flat elongated areas occurring along subduction and collision zones worldwide. We show that, in such basins, subsidence can be induced by earthquakes generated along bordering thrust faults due to coseismic displacement, postseismic displacement and liquefaction-induced compaction. As an example, the potential effects of earthquakes on the subsidence of Venice, which is located in the Po Plain foreland basin, are discussed. It is generally assumed that natural subsidence of Venice is continuous and that subsidence rates are rather constant through time. However, catastrophic pulses of subsidence cannot be ruled out as tought by the sudden disappearance of the island of Malamocco at the beginning of the XII century. The results of numerical models specifically run suggest that the risk of subsidence accelerations in Venice due to coseismic displacements is negligible. Modelling results from literature suggest that postseismic subsidence could be of the order of 1 cm. Although the effects of a single event should be improbably detectable, such a subsidence is not a priori negligible considering the number of seismogenic sources located within 100 km from the town. Historical sources are utilized to discuss the feasibility of liquefaction-induced subsidence in Venice. It is shown that the destruction and sinking of ancient Malamocco is roughly coincident with a strong earthquake cycle that was associated to phenomena that can be explained with liquefaction of sandy layers. Although the historical documents do not permit to establish a clear causal link between the earthquake and land subsidence, it is concluded that liquefaction-induced subsidence cannot be ruled out as a potential source for local subsidence acceleration.

Description: Submitted

Description: open

Description: The GSHAP CAUCAS test area was established under the INTAS Ct.94-1644 (Test Area for sismic Hazard Assessment in the Caucasus) and NATO ARW Ct.95-1521 (Historical and Prehistorical Earthquakes in the Caucasus), with the initial support of IASPEI, UNESCO and ILP. The high tectonic interest and seismicity rate of the whole area, the availability of abundant multi-disciplinary data and the long established tradition in hazard assessment provide a unique opportunity to test different methodologies in a common test area and attempt to establish some consensus in the scientific community. Starting from the same input data (historical and instrumental seismic catalogue, lineament and homogeneous seismic source models) six independent approaches to seismic hazard assessment have been used, ranging from pure historical deterministic to seismotectonic probabilistic and areal assessment methodologies. The results are here compared.

Description: JCR Journal

Description: open

Description: Earthquake Early Warning Systems (EEWS), based on real-time prediction of ground motion or structural response measures, may play a role in reducing vulnerability and/or exposition of buildings and lifelines. In fact, recently seismologists developed efficient methods for rapid estimation of event features by means of limited information of the P-waves. Then, when an event is occurring, probabilistic distributions of magnitude and source-to-site distance are available and the prediction of the ground motion at the site, conditioned to the seismic network measures, may be performed in analogy with the Probabilistic Seismic Hazard Analysis (PSHA). Consequently the structural performance may be obtained by the Probabilistic Seismic Demand Analysis (PSDA), and used for real-time risk management purposes. However, such prediction is performed in very uncertain conditions which have to be taken into proper account to limit false and missed alarms. In the present study, real-time risk analysis for early warning purposes is discussed. The magnitude estimation is performed via the Bayesian approach, while the earthquake localization is based on the Voronoi cells. To test the procedure it was applied, by simulation, to the EEWS under development in the Campanian region (southern Italy). The results lead to the conclusion that the PSHA, conditioned to the EEWS, correctly predicts the hazard at the site and that the false/missed alarm probabilities may be controlled by set up of an appropriate decisional rule and alarm threshold.

Description: Published

Description: 867–885

Description: open

Description: La definizione dell’attività di strutture tettoniche è un pre-requisito fondamentale per la comprensione delle caratteristiche sismotettoniche di un settore del territorio italiano che, come l’Appennino centrale, è stato interessato in tempi storici da eventi sismici di elevata magnitudo. Dunque, l’individuazione e la caratterizzazione dell’attività tardopleistocenica-olocenica di faglie potenzialmente responsabili di forti terremoti è di cruciale importanza in un’ottica di valutazione della pericolosità sismica. Nel presente lavoro vengono analizzate due faglie normali che interessano l’Appennino centrale, la faglia normale che delimita ad ovest la Montagna dei Fiori, uno dei rilievi più esterni della catena, e quella che borda a sud-ovest il bacino di Leonessa, con l’obiettivo di dare un contributo per una migliore definizione delle caratteristiche sismotettoniche di questo settore del territorio nazionale. La faglia normale della Montagna dei Fiori è una struttura lunga almeno 15 km la cui attività è stata responsabile della dislocazione di circa 900 m del substrato carbonatico. Il piano di faglia e la scarpata ad esso associata sono visibili in modo discontinuo lungo il versante. I rilevamenti geologici e geomorfologici effettuati chiariscono come l’esposizione del piano di faglia sia esclusivamente legata a fenomeni gravitativi, anche di grandi dimensioni, che interessano le formazioni calcareo-marnose (Scaglia Cinerea, Marne con Bisciaro, Marne con Cerrogna) affioranti al tetto della struttura, e a fenomeni di erosione selettiva fra le formazione della successione umbro-marchigiana affioranti al letto ed al tetto. La faglia, inoltre, è sigillata da una paleosuperficie di origine erosiva sospesa varie centinaia di metri al di sopra del fondovalle attuale del fiume Salinello (in località Colle Osso Caprino) e da brecce di versante (in località Pozzoranno) associabili a quelle riconosciute in modo ubiquitario in Appennino entrale ed attribuite al Pleistocene inferiore. Come per il caso della Montagna dei Fiori, il piano della faglia bordiera del bacino di Leonessa è visibile in modo discontinuo lungo i versanti che delimitano il settore meridionale della depressione. I nostri rilevamenti di terreno ci consentono di attribuire l’esposizione del piano i) a fenomeni gravitativi che interessano la fascia detritica depostasi alla base della scarpata di faglia e ii) a fenomeni di erosione selettiva fra i detriti ed il substrato carbonatico affiorante al letto della struttura tettonica, ad opera di corsi d’acqua perpendicolari al versante. Depositi di conoide alluvionale (“conoide alluvionale di Leonessa”) attribuiti da alcuni autori ad un contesto cronologico compreso fra la fine del Pleistocene inferiore ed il Pleistocene medio e che determinano una superficie terrazzata chiaramente visibile in tutto il bacino, non sembrano essere stati interessati (né dislocati né basculati) dall’attività di tale faglia. Inoltre, ulteriori due ordini di conoide alluvionale depostisi al di sopra di quello sopra citato ed attribuibili tentativamente al Pleistocene superiore, sigillano chiaramente la struttura tettonica. Dunque, dalle nostre osservazioni si evince che, per quello che riguarda la faglia normale della Montagna dei Fiori, tale struttura tettonica non risulta essere attiva almeno a partire dal Pleistocene inferiore e che l’esposizione del piano di faglia è esclusivamente legata a fenomeni gravitativi e di morfoselezione. Ciò corroborerebbe quanto proposto da altri autori che attribuiscono a questa struttura tettonica esclusivamente un’attività pre- e sin- fase tettonica compressiva. Per quello che riguarda il bacino di Leonessa, è possibile ipotizzare che la faglia bordiera sia stata attiva fino al Pleistocene inferiore, creando lo spazio per l’accumulo dei depositi del conoide alluvionale di Leonessa. L’attività sarebbe poi terminata, o quantomeno si sarebbe ridotta ad un tasso decisamente inferiore a quello degli agenti morfodinamici, a partire dal Pleistocene medio.

Description: Unpublished

Description: Camerino (MC), Italia

Description: 3.2. Tettonica attiva

Description: open

Description: The NNE-trending Yangsan Fault (YSF) is the most prominent fault in the southeastern part of the Korean Peninsula and has a continuous trace about 200 km long. Activity on this fault was recently investigated using aerial photographs, topographic analysis, and trenching. The geomorphologic evidence of Late Quaternary faulting is clearly recognized on both the northern (Yugyeri and Tosung-ri areas) and southern parts (Eonyang to Tongdosa area) of the fault. The main YSF is marked by a zone of shattered rock that is tens of meters wide and zone of fault gouge. During the Late Quaternary, right-lateral movement occurred mainly on the southern part, as shown by lowangle striations on the fault plane, elongation of deformation features in the fault gouge. The estimated vertical slip rate is about 0.02-0.07 mm/yr, and the lateral slip rate may be several times larger than the vertical rate. The most recent event occurred prior to deposition of Holocene alluvium. In the northern part, the fault locally changes trend to almost N-S, dips to the east and has reverse movement. The average vertical slip rate is estimated less than 0.1 mm/yr. The most recent event probably occurred after 1314 cal. years BP (A.D. 536).

Description: Published

Description: JCR Journal

Description: open

Description: The plain of Gubbio is located in a northwest-southeast oriented, 4-km wide, 20-km long intermountain basin in the northern Apennines, central Italy. The moderate-magnitude earthquakes of the 1997 Umbria-Marche seismic sequence, occurred 40 km southeast of Gubbio, generated displacements as large as 6 cm within the basin. The large amplitude phase, not observed outside of the basin, was followed by low-frequency wave trains lasting up to 1 minute. In order to investigate the mechanism of possible local amplification effects, different kind of geophysical and geological investigation of the basin started within the framework of the Italian DPC-INGV projects. In particular, the GFZ and the INGV deployed two linear seismic arrays. The first one was composed of ten seismological stations with 1-s receivers. It operated from June until December 2005. The array was oriented north-south, approximately: all the stations but two were installed on the sedimentary deposits. The remaining two stations (the northernmost and the southernmost) were installed on rock outcrops at the edges of the basin. The second array, composed by 10 stations with 5-s receivers, was deployed along the main axis of the basin, and is recording since November 2005. For 45 days, the two arrays worked simultaneously. A selected dataset of 250 earthquakes has been analyzed. H/V spectral ratio results show that systematic low-frequency (0.3-0.4 Hz) amplification affects the stations in the middle of the basin. The resonance frequency peaks are consistent with the thickness and the average S-wave velocity of soft sediments derived from microtremor measurements in the basin. The conventional spectral ratio results show a more complex broad-band (0.3-10 Hz) amplification. The analysis of selected records by means of a sonogram approach highlights the arrival of strong late phases increasing the signal duration at the stations located in the middle of the basin.

Description: Unpublished

Description: Geneva, Switzerland

Description: open

Description: The huge loss of lives and the destruction caused by the 2004 Indian Ocean tsunami dramatically showed the need for a reassessment of tsunami hazard and risk in coastal regions prone to this threat. It is known that many countries facing the Mediterranean basin have been affected by several tsunamis in the past, some of which were catastrophic over large areas. Our work aims to quantitatively address the problem of the tsunami hazard and risk assessment by means of numerical simulation of earthquake-induced tsunami scenarios. The work is part of a larger project, funded by the Italian Department for Civil Defense, whose main goal is the evaluation of the seismogenic potential and of the probability of occurrence of strong earthquakes in Italy. Here we show some preliminary results concerning the analysis of several simulated tsunami scenarios. On the basis of tsunami catalogues and seismogenic source databases, we selected a set of tectonic sources that, owing to their location and/or size, are believed to be especially hazardous for the Italian coasts. Once the geometrical parameters of the fault are defined (on the basis of geological and seismological evidence and constraints), we compute the coseismic vertical displacement of the seafloor, which represents the initial condition of the tsunami propagation problem. Then we solve the propagation equations (the wide used shallow-water equations) through a finite difference technique. The main outputs of a single run are the wavefields at desired times, useful to estimate the arrival times of the wavefronts, and the maximum water elevation field that gives at-glance information on the tsunami energy focusing during the whole propagation. Furthermore, for those stretches of coast that are particularly vulnerable (owing to high population density, presence of important infrastructures, etc.) we make a more detailed analysis of the wave impact. Among the tectonic sources we studied, the 365 AD Crete earthquake indeed represents a serious threat for the Italian coastlines facing the Ionian Sea, where we estimated a wave height exceeding 1-2 meters along hundreds of km of the coast. Furthermore, the first wavefront from this source is expected to reach the coasts of southern Italy in less than 1 hour from the origin time of the parent earthquake. This finding stresses the need for an especially early warning by the geophysical monitoring systems and by the Civil Defense structures.

Description: Convenzione INGV - DPC 2004-2006 Progetti Sismologici e Vulcanologici di interesse per il Dipartimento della Protezione Civile Progetto S2 - Valutazione del potenziale sismogenetico e probabilità dei forti terremoti in Italia

Description: Published

Description: Vienna, Austria

Description: open

Description: Five Andean countries (Bolivia, Peru, Ecuador, Colombia, Venezuela) and four European countries (Italy, Spain, Holland, Germany) cooperated in the PILOTO program ("Test area for earthquake monitoring and seismic hazard assessment"), launched under GSHAP and sponsored by the European Union (Ct.94-0103) to produce a unified SHA for the Andean region. Activities included the integration of national earthquake catalogues and source zonings in common regional databases and joint technical workshops for the assessment of the regional hazard, expressed in terms of expected peak ground acceleration with 10% exceedance probability in 50 years.

Description: JCR Journal

Description: open

Description: This article presents the results of a detailed study of the effects of the 1883 earthquake, which occurred at the island of Ischia (Gulf of Naples) and produced the total destruction of buildings in the epicentral area (Casamicciola town). Despite the moderate magnitude, this event was characterised by very high intensities (Imax = XI degree MCS) mainly due to the shallow depth of the source. The study of the earthquake shows that the intensities, which decreased rapidly with distance, were affected by source directivity, according to the causative fault geometry and tectonic structures, while local amplification of damage was observed where soft soils outcrop. The attenuation of seismic intensity with distance was evaluated using the well-known relation of intensity versus epicentral distance (Blake’s method). The diverse gradients of attenuation, observed in different directions, were ascribed to the various geological features of the shallow crust of the island. In order to evaluate the role of geology in the damage level, we computed different attenuation models for stiff and soft soils outcropping on the island. A systematic local amplification of about 1 MCS degree associated to the presence of reworked tuffs was obtained. This study also shows the influence of geological conditions on the evaluation of macroseismic data and supplies useful elements to derive a predictive map of potential site effects.

Description: Published

Description: id 231

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: reserved

Description: Although the Altyn Tagh Fault (ATF) is thought to play a key role in accommodating India-Eurasian convergence, little is known about its earthquake history. Studies of this strike-slip fault are important for interpretation of the role of faulting versus distributed deformation in the accommodation of the India- Eurasia collision. In addition, the 〉 1200 km long fault represents one of the most important and exemplary intracontinental strike-slip faults in the world. We mapped fault trace geometry and interpreted paleoseismic trench exposures to characterize the seismogenic behavior of the ATF. We identified 2 geometric segment boundaries in a 270 km long reach of the central ATF. These boundaries define the westernmost Wuzhunxiao, the Central Pingding, and the easternmost Xorxol (also written as Suekuli or Suo erkuli) segments. In this paper, we present the results from the Camel paleoseismic site along the Xorxol Segment at 91.759°E, 38.919°N. There evidence for the last two earthquakes is clear and 14C dates from layers exposed in the excavation bracket their ages. The most recent earthquake occurred between 1456 and 1775 cal A.D. and the penultimate event was between 60 and 980 cal A.D. Combining the Camel interpretations with our published results for the central ATF, we conclude that multiple earthquakes with shorter rupture lengths (?? 50 km) rather than complete rupture of the Xorxol Segment better explain the paleoseismic data. We found 2-3 earthquakes in the last 2-3 kyr. When coupled with typical amounts of slip per event (5-10 m), the recurrence times are tentatively consistent with 1-2 cm/yr slip rates. This result favors models that consider the broader distribution of collisional deformation, rather than those with northward motion of India into Asia absorbed along a few faults bounding rigid blocks.

Description: Published

Description: JCR Journal

Description: open

Description: Results of probabilistic seismic hazard assessment (PSHA), in terms of macroseismic intensity applied to the Mt. Etna region, are presented. PSHA has been performed using a numerical procedure based on the extensive use of local macroseismic information, as an alternative to the usual Cornell-McGuire methods. The large amount of intensity data available for this area - coming from the Italian intensity database DBMI04 for the regional earthquakes, and from the Etna catalogue for the ‘local’ events - has provided fairly exhaustive seismic site histories (i.e. the data set of macroseismic observations available for a given locality) to estimate the seismic hazard for 402 localities on the volcano. In order to improve the completeness of the site catalogue when historical information is missing, observed intensity data have been integrated with values calculated from epicentral information obtained by using an attenuation law specific for the Etna region. Using a probability distribution considering the completeness of the input database and the uncertainty of intensity data, the hazard in terms of maximum intensity (Iexp) characterised by a 10% probability of exceedance in an exposure time of 50 years, has been computed. The highest values ( Iexp = IX or X) are found in the south-eastern flank of Mt. Etna while the rest of the volcano is exposed to a lower hazard (Iexp = VIII). Despite the low energy (M≤4.8) compared with that of the large regional earthquakes affecting the area (6.6≤M≤7.4), the local events strongly influence the pattern of the hazard in the eastern sector of Mt. Etna, representing a significant, and sole, source of hazard when a shorter exposure time (e.g. 30 years) is considered.

Description: Published

Description: 77-91

Description: N/A or not JCR

Description: reserved

Description: Probabilistic seismic hazard analysis is currently the soundest basis for the rational evaluation of ground-motion hazard for site-specific engineering design and assessment purposes. An increasing number of building codes worldwide acknowledge the uniform hazard spectra as the reference to determine design actions on structures and to select input ground motions for seismic structural analysis. This is the case, for example, in Italy where the new seismic code also requires the seismic input for nonlinear dynamic analysis to be selected on the basis of dominating events, for example, identified via disaggregation of seismic hazard. In the present study, the design earthquakes expressed in terms of representative magnitude (M), distance (R), and ε were investigated for a wide region in the southern Apennines, Italy. To this aim, the hazards corresponding to peak ground acceleration and spectral acceleration at 1 sec with a return period of 475 yr were disaggregated. For each of the disaggregation variables the shape of the joint and marginal probability density functions were studied. The first two modes expressed by M, R, and ε were extracted and mapped for the study area. The results shown provide additional information, in terms of source and ground-motion parameters, to be used along with the standard hazard maps to better select the design earthquakes. The analyses also allow us to assess how various frequency ranges of the design spectrum are differently contributed by seismic sources in the study area.

Description: Published

Description: 2979–2991

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: JCR Journal

Description: reserved

Description: The Mesa del Caballo trench assessment confirms the Holocene activity of the main strand of the Boconó fault at the Apartaderos pull-apart basin. Fifteen earthquakes, of which fourteen have been radiocarbon dated, have been recognized, spanning the last 20,500 yr. Recurrence intervals of these ≥7 magnitude events are variable. The dominant mode of recurrence is 400–450 yr, and the second one is 900 yr. Eventually some events are 1400–1800 yr apart. We suspect that our seismic record may be incomplete. This could be easily justified by several conditions: most of the earthquake recognitions is based on open-crack filling and they superpose spatially (eventually masking or destroying older fills), trenching may miss some events because the fault is made of en echelon Riedel shears, and a short return period may lead to faint differences between paleosoils few hundreds years of age apart. This trench also images an older activity of the fault, as evidenced by plentiful earthquake-triggered liquefaction features, as well as slumping and rotational sliding. By comparing paleoseismic results between the Morro de Los Hoyos and Mesa del Caballo trenches, it appears that both fault strands bounding the Apartaderos pull-apart basin move simultaneously. Besides, the main strand also coseismically slips twice in between those common events. In other words, the seismic scenario could be that the northern strand recurs every 1200–1350 yr while the southern does every 400– 450 yr. This is also in agreement with a respective slip share of 25 and 75% of the 9–10 mm/yr average slip of the Boconó fault in the Mérida Andes central sector.

Description: Published

Description: 38-53

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: On September 6, 2002, aML =5.6 earthquake, occurring some tens of kilometres offshore from the Northern Sicilian coast (Southern Tyrrhenian Sea), slightly damaged the city of Palermo and surroundings (degree 6 in the European Macroseismic Scale 1998). The macroseismic investigation of the shock and a detailed study of effects of the main earthquakes which affected Palermo in the past have been performed in order to evaluate the seismic response of the city. Moreover, the comparison of the recent event, which is instrumentally constrained, with historical earthquakes allows us to infer new insights on the seismogenic sources of the area, that seem located offshore in the Tyrrhenian sea. In the last 500 years, Palermo has never been completely destroyed but has suffered effects estimated between intensities 6 and 8 EMS-98 many times (1693, 1726, 1751, 1823, 1940, 1968, 2002). The damage scenarios of the analysed events have shown that damage distribution is strongly conditioned by soil response in the different parts of the city and by a high building vulnerability, mainly in the historical centre and in the south-eastern zone of the modern city. As a matter of fact, Palermo has always suffered greater effects than those reported for other nearby localities. The hazard assessment obtained using observed site intensities has shown that the probability of occurrence for intensity 8 (the strongest intensity observed in Palermo) exceeds 99% for 550 years, while the estimated mean return period is 152 ± 40 years. These results, in connection with building vulnerability due to the urban expansion before the introduction of seismic code, suggest that the city is exposed to a relatively high seismic risk.

Description: Published

Description: 525-543

Description: partially_open

Description: Vengono presentate le stime di pericolosità sismica, in termini di intensità macrosismica, ottenute mediante l’approccio probabilistico proposto da Albarello e Mucciarelli (2002), basato sull’impiego dei dati documentari relativi agli effetti locali prodotti dai terremoti passati (storie sismiche di sito). I risultati forniti da questa procedura (approccio “di sito”), in termini di minimo valore di intensità caratterizzato da una probabilità di eccedenza inferiore al 10% in 50 anni (Iref), sono confrontati con quelli ottenuti sul territorio italiano tramite la metodologia “standard” di Cornell-McGuire. Per meglio comprendere i motivi delle differenze osservate tra le due stime e il ruolo di differenti basi informative, sono state prodotte diverse mappe di pericolosità. Stime di pericolosità a scala locale sono state inoltre effettuate nell’area dell’Etna dove, grazie a numerosi studi macrosismici di dettaglio, sono disponibili storie sismiche di sito particolarmente ricche.

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: The North Tabriz Fault is a major seismogenic fault in NW Iran. The last damaging earthquakes on this fault occurred in 1721, rupturing the southeastern fault segment, and in 1780, rupturing the northwestern one. The understanding of the seismic behavior of this fault is critical for assessing the hazard in Tabriz, one of the major cities of Iran; the city suffered major damage in both the 1721 and 1780 events. Our study area is located on the northwestern fault segment, west of the city of Tabriz. We performed geomorphic and trenching investigations, which allowed us to recognize evidence for repeated faulting events since the Late Pleistocene. From the trenches, we found evidence for at least four events during the past 3.6 ka, the most recent one being the 1780 earthquake. On the basis of different approaches, horizontal slip per event and slip rates are found in the ranges of 4 ± 0.5 m and 3.1-6.4 mm/yr, respectively. We also attempted an estimate of the average recurrence intervals which appears to be in the range 350-1430 years, with a mean recurrence interval of 821 ± 176 years. On the basis of these results, the northwestern segment of the North Tabriz Fault does not appear to present a major seismic potential for the near future, however, not enough is known about the southeastern segment of the fault to make a comparable conclusion.

Description: Published

Description: JCR Journal

Description: open

Description: A seismic rehabilitation program is being implemented to address the vulnerability of a large proportion of Italian building stock. A risk management framework, initially only for Italian school buildings, has been developed to assign priorities for the rehabilitation, and to give timescales within which retrofit or demolition must take place. Since it is not practical to carry out detailed assessment for around 60,000 Italian schools, the framework is a multiple-level procedure that aims to identify the highest-risk buildings based on filters of increasing detail, and reduces the size of the building inventory at each step. Finally, priorities and timescales are assigned based on vulnerability, seismic hazard, and building occupancy, within a general framework with parameters that must be assigned by the relevant authorities. The methodology is transparent, technically based, and flexible enough to be adapted for other building types or regions.

Description: DPC — Dipartimento della Protezione Civile

Description: Published

Description: 291-314

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: reserved

Description: Earthquake early warning systems (EEWS), based on real-time prediction of ground motion or structural response measures, may play a role in re- ducing vulnerability and/or exposure of buildings and lifelines. Indeed, seismologists have recently developed efficient methods for real-time es- timation of an event’s magnitude and location based on limited informa- tion of the P-waves. Therefore, when an event occurs, estimates of magni- tude and source-to-site distance are available, and the prediction of the structural demand at the site may be performed by Probabilistic Seismic Hazard Analysis (PSHA) and then by Probabilistic Seismic Demand Analysis (PSDA) depending upon EEWS measures. Such an approach contains a higher level of information with respect to traditional seismic risk analysis and may be used for real-time risk management. However, this kind of prediction is performed in very uncertain conditions which may affect the effectiveness of the system and therefore have to be taken into due account. In the present study the performance of the EWWS under development in the Campania region (southern Italy) is assessed by simu- lation. The earthquake localization is formulated in a Voronoi cells ap- proach, while a Bayesian method is used for magnitude estimation. Simu- lation has an empirical basis but requires no recorded signals. Our results, in terms of hazard analysis and false/missed alarm probabilities, lead us to conclude that the PSHA depending upon the EEWS significantly improves seismic risk prediction at the site and is close to what could be produced if magnitude and distance were deterministically known.

Description: Published

Description: 211-232

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: reserved

Description: In this paper we present the results of preliminary geomorphic and trenching investigations along the Kahrizak fault. This fault is located south of the highly populated metropolis of Tehran and represents one of the main structures in the area containing important seismic potential. The Kahrizak fault has a very clear expression at the surface where it forms a prominent 35-km-long, 15-m-high scarp on Holocene alluvial deposits. The fault strikes N70°-80°W and dips to the north. Movement is prevalently right-lateral with the northern side of the fault up. Trench excavations exposed a sequence of weathered, massive, alluvial deposits which are dated, by means of radiometric methods, to the Holocene. In the trenches the sequence is intensely deformed by north-dipping, high- and low-angle faults within a 30-m-wide zone. On the basis of stratigraphic and structural relations, some evidence for individual Holocene earthquakes is found; however, we were not able to reconstruct the seismic history of the fault nor to evaluate the size of deformation produced by each event. Because of the possible ~10 m offset of ancient linear hydraulic artifacts (qanáts), that cross the fault, we hypothesize that the most recent event may have occurred in historical times (more recent than 5000 yr B.P.) and it may be one of those reported in this area by the current catalogues of seismicity. Based on these preliminary investigations we estimate an elapsed time between 5000 and 800 years, a maximum slip per event dmax of ~10 m, a minimum Holocene vertical slip rate of ~1 mm/yr versus a horizontal slip rate of ~3.5 mm/yr, a maximum of ~3000 years for the average recurrence time, and an expected Mw = 7.0 to 7.4. These can be considered as a first-hand reference for the activity on this fault.

Description: Published

Description: 187-199

Description: 3.2. Tettonica attiva

Description: N/A or not JCR

Description: reserved

Description: The Calabrian arc represents an accretionary wedge located between the southern Apennines and the Maghrebian chain from which it is separated by two regional shear zones, i.e. the “Pollino Line” and “Taormina Line”, respectively. Since the Pliocene, extension affected the Calabrian chain, determining the formation of normal faults systems. Paleoseismological investigations allowed to associate some of the strongest historical earthquakes occurred in the Calabrian region (Mw up to 7.5) to some of these normal faults. We analyse the north-eastern sector of the arc which is characterised by a complex structural setting, being affected by the Pollino Line. Indeed, an ~E-W trending fault system (Rossano Fault) cut the area. This fault system displays a complex kinematic history, with the superimposition, during the Quaternary, of a normal kinematics over an older strike-slip one. About two km SE of the Mirto village, an excavation exposed marine deposits, attributed by means of paleontological analyses to an age not older than the Lower Pleistocene, overlain by alluvial-colluvial sediments. These deposits have been deformed by a compressive, NW-SE trending fault, verging landwards. The continental sediments affected by the fault have been radiocarbon dated between 10.018±43 BP and 8397±47 BP. This fault may represent the surficial expression of 1) a splay of a back-thrust, related to a main active thrust verging towards NE or 2) an active NW-SE transpressive fault or 3) a local compressive deforma-tion (i.e. a restraining bend) related to an active strike-slip fault. Works are still in progress in order to define the relationship of this compressive fault with the near Rossano fault, to which Galli et al (2006d) attributes a Late Holocene normal activity, considering that this sector has been struck in 1836 by a strong earthquake (Mw=6.2), the causative fault of which has been only tentatively related to the aforementioned Rossano fault.

Description: Published

Description: Crete, Greece

Description: 3.2. Tettonica attiva

Description: open

Description: Convenzione INGV-DPC 2004 – 2006 / Progetto S1 Proseguimento della assistenza al DPC per il completamento e la gestione della mappa di pericolosità sismica prevista dall'Ordinanza PCM 3274 e progettazione di ulteriori sviluppi

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: On November 3, 2002, a moment-magnitude (Mw) 7.9 earthquake produced 340 km of surface rupture on the Denali fault and two related faults in central Alaska. The rupture, which proceeded from west to east, began with a 40-km-long break on a previously unknown thrust fault. Estimates of surface slip on this thrust were 3-6 m. Next came the principal surface break, along 220 km of the Denali fault. There, right-lateral offset averaged almost 5 m and increased eastward to a maximum of nearly 9 m. Finally, slip turned southeastward onto the Totschunda fault, where dextral offsets up to 3 m continued for another 70 km. This three-part rupture ranks among the longest documented strike-slip events of the past two centuries. The surface-slip distribution supports and clarifies models of seismological and geodetic data that indicated initial thrusting followed by rightlateral strike slip, with the largest moment release near the east end of the Denali fault. The Denali fault ruptured beneath the Trans-Alaska oil pipeline. The pipeline withstood almost 6 m of lateral offset, because engineers designed it to survive such offsets based on pre-construction geological studies. The Denali fault earthquake was typical of large-magnitude earthquakes on major intracontinental strike-slip faults, in the length of the rupture, the multiple fault strands that ruptured, and the variable slip along strike.

Description: Published

Description: 565-578

Description: open

Description: The supposed b-value spatial variability is the central topic of many scientific works dealing with forecasting modeling applications or geological correlations. If used for seismicity rates determination, the b-value plays an important role in probabilistic seismic hazard assessment, but how much does it influence PSHA? In the logic tree approach used for the new probabilistic seismic hazard map of Italy, named MPS04 (MPS Working Group, 2004), one of the sources of epistemic uncertainty considered was the procedure for computing seismicity rates. Two alternatives were adopted: 1) compute the activity rates for each binned magnitude class and 2) compute a Gutenberg-Richter (1944) distribution. In the logic tree branches where Gutenberg-Richter distribution was adopted, the corresponding bvalue was evaluated for each seismogenic zone: it spans between 0.63 and 2.01. After analysing the b-value variability in the Italian region, this work evaluates the impact of setting the b-value equal to 1 on the results of seismic hazard assessment in terms of PGA and energy release compared to the choices adopted for MPS04 (MPS Working Group, 2004).

Description: Published

Description: 59-76

Description: 4T. Sismicità dell'Italia

Description: N/A or not JCR

Description: open

Description: Nuovi dati archeosismologici dell'Appennino abruzzese (Italia centrale)

Description: Published

Description: Palazzo Sant'Agostino Salerno Italy

Description: 3.10. Sismologia storica e archeosismologia

Description: open

Description: The development and implementation of an earthquake early warning system (EEWS), both in regional or on-site configurations can help to mitigate the losses due to the occurrence of moderate-to-large earthquakes in densely populated and/or industrialized areas. The capability of an EEWS to provide real-time estimates of source parameters (location and magnitude) can be used to take some countermeasures during the earthquake occurrence and before the arriving of the most destructive waves at the site of interest. However, some critical issues are peculiar of EEWS and need further investigation: (1) the uncertainties on earthquake magnitude and location estimates based on the measurements of some observed quantities in the very early portion of the recorded signals; (2) the selection of the most appropriate parameter to be used to predict the ground motion amplitude both in near-and far-source ranges; (3) the use of the estimates provided by the EEWS for structural engineering and risk mitigation applications. In the present study, the issues above are discussed using the Campania–Lucania region (Southern Apennines) in Italy, as test-site area. In this region a prototype system for earthquake early warning, and more generally for seismic alert management, is under development. The system is based on a dense, wide dynamic accelerometric network deployed in the area where the moderate-to-large earthquake causative fault systems are located. The uncertainty analysis is performed through a real-time probabilistic seismic hazard analysis by using two different approaches. The first is the Bayesian approach that implicitly integrate both the time evolving estimate of earthquake parameters, the probability density functions and the variability of ground motion propagation providing the most complete information. The second is a classical point estimate approach which does not account for the probability density function of the magnitude and only uses the average of the estimates performed at each seismic station. Both the approaches are applied to two main towns located in the area of interest, Napoli and Avellino, for which a missed and false alarm analysis is presented by means of a scenario earthquake: an M 7.0 seismic event located at the centre of the seismic network. Concerning the ground motion prediction, attention is focused on the response spectra as the most appropriate function to characterize the ground motion for earthquake engineering applications of EEWS.

Description: Published

Description: On line First

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: JCR Journal

Description: reserved

Description: Il settore dell’arco Calabro è interessato da sistemi di faglie normali attive, responsabili di forti terremoti storici di Magnitudo superiore a 6. Gli eventi sismici maggiori sono avvenuti principalmente tra lo stretto di Messina e la valle del Crati. Tra questi il terremoto del 1783 (M=6.9), del 1905 (M=7.3), del 1638 (M=6.7), del 1832 (M=6.5) e del 1836 (M=6.2) (Working Group CPTI 04). Alcuni di questi eventi sono stati associati all’attivazione di alcune strutture tettoniche (Galli & Scionti 2006; Galli & Bosi 2002; Valensise & Pantosti 2001). L’evento del 1836, che ha colpito il settore nord-orientale della Calabria, poco a sud della piana di Sibari, è stato associate tentativamente da Moretti (2000) all’attivazione di una serie di segmenti di faglia orientati E-W e NW-SE individuati tra Corigliano e Rossano. Questo lavoro ha come scopo quello di individuare strutture sismogenetiche attive nell’area colpita dall’evento sismico del 1836 ed, in particolare, quelle causative dell’evento sismico del 1836. A tal fine sono stati effettuati rilevamenti geologici e geomorfologici, con particolare riguardo alla zona dell’abitato di Mirto, poco a sud della città di Rossano Calabro, dove uno scavo ha messo in evidenza depositi di origine marina in facies deltizia, datati per via paleontologica ad un’età non più antica dell’Emiliano (Pleistocene inferiore), dislocati da una struttura tettonica ad orientazione circa NNW-SSE, a cinematica prevalentemente inverse, con senso di trasporto verso SSW. La dislocazione sembra interessare anche depositi continentali fluvio-colluviali incassati all’interno dei depositi deltizi e separati da questi da una superficie di erosione. Da questi sedimenti continentali è stato prelevato un campione per effettuare una datazione radiometrica, ancora in corso. La localizzazione di questa struttura tettonica è compatibile con l’ubicazione della zona epicentrale del terremoto del 1836, derivata dai dati macrosismici (CPTI 04). Inoltre, lungo il lineamento, pochi km a nord dello scavo studiato, in località Cento Fontane, viene segnalata risorgenza di acque calde in occasione dell’evento sismico menzionato.

Description: Published

Description: Firenze, Italia

Description: 3.2. Tettonica attiva

Description: open

Description: Earthquake Early Warning Systems (EEWS), based on real-time prediction of ground motion or structural response measures, may play a role in reducing vulnerability and/or exposition of buildings and lifelines. In fact, recently seismologists developed efficient methods for rapid estimation of event features by means of limited information of the P-waves. Then, when an event is occurring, probabilistic distributions of magnitude and source-to-site distance are available and the prediction of the ground motion at the site, conditioned to the seismic network measures, may be performed in analogy with the Probabilistic Seismic Hazard Analysis (PSHA). Consequently the structural performance may be obtained by the Probabilistic Seismic Demand Analysis (PSDA), and used for real-time risk management purposes. However, such prediction is performed in very uncertain conditions which have to be taken into proper account to limit false and missed alarms. In the present study, real-time risk analysis for early warning purposes is discussed. The magnitude estimation is performed via the Bayesian approach, while the earthquake localization is based on the Voronoi cells. To test the procedure it was applied, by simulation, to the EEWS under development in the Campanian region (southern Italy). The results lead to the conclusion that the PSHA, conditioned to the EEWS, correctly predicts the hazard at the site and that the false/missed alarm probabilities may be controlled by set up of an appropriate decisional rule and alarm threshold.

Description: Published

Description: Geneva, Switzerland.

Description: open

Description: A new approach has been developed aiming at the probabilistic estimate of seismic hazard from the local seismic history. This is expressed in terms of seismic effects documented at the site during past earthquakes (macroseismic intensity) and thus a specific statistical treatment is required to take into account the peculiar character of macroseismic data that are discrete, ordinal and range-limited. The proposed procedure also allows the correct treatment of relevant uncertainty (ill-defined intensity values, local catalogue completeness, etc.) in the frame of a coherent distribution-free statistical approach. This methodology has been implemented in a free computer program (SASHA: Site Approach to Seismic Hazard Assessment) and applied to the seismic hazard estimation at the 8100 municipalities in Italy. The program also implements a probabilistic procedure to “translate” hazard estimates provided in terms of Intensity to other ground-shaking parameters (e.g. PGA): this “rescaling” procedure allows to com-pare the results coming from this approach with those provided by standard PSHA procedures. This comparison results of great importance at the sites where a relatively rich seismic history is available and it could provide a benchmark for different approaches to PSHA.

Description: Unpublished

Description: Hersonissos, Crete, Greece

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: The outermost, NE-verging fronts of the Northern Apennines (Italy) are overlain by a thick syntectonic sedimentary wedge filling up the basin beneath the Po Plain. Due to fast sedimentation rates and comparatively low tectonic rates, the fronts are generally buried. Evidence for their activity includes scattered historical and instrumental earthquakes and drainage anomalies controlled by growing buried anticlines. The largest earthquakes, up to Mw 5.8, are associated with active compression with a GPS-documented shortening rate 〈1 mm/a. We used geological, structural and morphotectonic data to draw a N-S–striking section between Bologna and Ferrara, aimed at analyzing whether and how the deformation is partitioned among the frontal thrusts of the Northern Apennines and identifying the potential sources of damaging earthquakes. We pointed out active anticlines based on the correspondence among drainage anomalies, historical seismicity and buried ramps. We also analyzed the evolution of the Plio-Quaternary deformation by modeling in a sandbox the geometry, kinematics and growth patterns of the thrust fronts. Our results (i) confirm that some of the main Quaternary thrusts are still active and (ii) highlight the partitioning of deformation in the overlap zones. We remark that the extent and location of some of the active thrusts are compatible with the location and size of the main historical earthquakes and discuss the hypothesis that they may correspond to their causative seismogenic faults.

Description: In press

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: open

Description: EC Project EVG1-CT-2002-00069 RELIEF Project Partner 2: Istituto Nazionale di Geofisica e Vulcanologia, Roma, ITALY

Description: Unpublished

Description: open

Description: The DISS (extensively described elsewhere in this session: also available at http://www.ingv.it/DISS/) is a large and fully georeferenced repository of tectonic, fault and paleoseismological information on Italy. The new version 3.0.2 contains over 120 “Individual Seismogenic Sources”, over 75 “Seismogenic Areas”, over 300 “Macroseismic Seismogenic Sources”, all complemented by over 700 images, about 2,000 references and a number of maps and datasets regarding widely diverse geophysical datasets. The data analysis tools supplied by DISS’ GIS engine allow the user to select, overlay and process several types of data and to perform spatial and statistical analyses. For all of these reasons DISS is not simply an archive of outcrop-scale field data, but rather a precious tool that allows the seismogenic process to be represented and investigated in 3D and at various scales, and particularly at regional scale. One of the key points in the design of the structure of the Dabatase was the full exploitation of basic physical constraints concerning the rates of crustal deformation, the continuity of deformation belts, the spatial relationships between adjacent faults, both at the surface and at depth.

Description: INGV

Description: Unpublished

Description: Vienna

Description: open

Description: The November 12, 1999, Mw 7.1 earthquake, ruptured the Düzce segment of the North Anatolian Fault Zone and produced ca. 40 km-long surface ruptures. To learn about recurrence of large surface faulting earthquakes on this fault, we undertook paleoseismological trench investigations. We found evidence for repeated surface faulting paleoearthquakes pre-dating the 1999 event. Dating was based on radiocarbon and 210Pb analyses as well as on archaeological considerations. By merging information obtained from all the trenches we reconstructed the seismic history of the Düzce fault for the past millennium. We correlated coeval events between different trench sites under the assumption that, similarly to the 1999 event, paleoearthquakes ruptured the whole Düzce fault. Besides the 1999 earthquake, prior surface faulting earthquakes are dated as follows: AD1685-1900 (possibly end of 19th century); AD1685-1900 (possibly close to AD 1700); AD1185-1640; AD685-1220 (possibly AD800-1000). Thus, the AD1719, AD1878 and AD1894 historical earthquakes, may have ruptured the Düzce fault and not the faults they are usually associated to or, alternatively, a cascade of events occurred on the Düzce and nearby faults (similarly to the Izmit and Düzce 1999 earthquakes). Five events since AD 685-1220 (possibly AD800-1000), would yield an average recurrence time for the Düzce fault, of 200-325 yr (possibly 250-300 yr). The three most recent earthquakes, including 1999, occurred within 300 yr and may be suggestive of clustering. Assuming that the average 1999 slip is characteristic for this fault, the above recurrence times yield slip rates of 6.7-13.5 mm/yr.

Description: E.C. project Relief (EVG1-CT-2002-00069)

Description: Submitted

Description: open

Description: The city of Palermo (southern Italy) was severely damaged in the past by moderate-magnitude earthquakes located tens of kilometres offshore. The historical monumental heritage and the high density of population motivated large efforts for the seismic risk assessment. We present the geological and seismological studies performed in downtown Palermo as a study case to show how the complexity of an urban environment can be approached with multidisciplinary investigations. Downtown Palermo is characterized by sea deposits in the coastal zone and the alluvial deposits of two rivers (Papireto and Kemonia) of about 150 m width, which were buried and filled during the XVII century. The difficulty of surface geological surveys was compensated through an analysis of aerial photos and more than 2000 borehole data organized in the City-GIS of the Department of Geology and Geodesy of the University of Palermo. A previous study on the well-documented historical damage indicated the major role played by the two river valleys and the sea deposits in controlling the damage distribution, above the assumption of a fairly homogeneous vulnerability of the existing buildings in downtown. To test the feasibility of using ambient noise for recognizing the presence of alluvial deposits in a densely urbanized environment, a large microtremor measurement campaign was performed in Palermo across several profiles. The frequency peaks inferred from the horizontal-to-vertical spectral ratio were compared with numerical simulations to assess the seismic velocity profile and the soil stratigraphy. Moreover, noise data were analyzed through a statistical approach to establish a possible correlation between damage, resonance frequency and amplitude, and geology. After the moderate earthquake of September 6, 2002 (Mw=5.9, 50 km far away), the analysis of the aftershock sequence provided a well documented estimate of the variation of ground motion within the city in the case of linear soil response. Using these aftershocks we computed also synthetic accelerograms of the main shock through Empirical Green’s Functions that provided ground accelerations as large as 50 gals, consistently with the documented EMS-98 intensity. Synthetic accelerograms showed a large variability of horizontal ground motion within the city (a factor of 3 – 4) that confirms the role of local geology in causing an increase of the seismic hazard on sea and alluvial deposits. Finally, we discuss the comparison between the acceleration response spectra calculated for different soil categories and the design elastic spectra provided by EC8.

Description: Unpublished

Description: Lisbon, Portugal

Description: open

Description: The development of the 2004–2005 eruption at Etna (Italy) is investigated by means of field surveys to define the current structural state of the volcano. In 2004–2005, a fracture swarm, associated with three effusive vents, propagated downslope from the SE summit crater towards the SE. Such a scenario is commonly observed at Etna, as a pressure increase within the central conduits induces the lateral propagation of most of the dikes downslope. Nevertheless, some unusual features of this eruption (slower propagation of fractures, lack of explosive activity and seismicity, oblique shear along the fractures) suggest a more complex triggering mechanism. A detailed review of the recent activity at Etna enables us to better define this possible mechanism. In fact, the NW–SE-trending fractures formed in 2004–2005 constitute the southeastern continuation of a N–S-trending fracture system which started to develop in early 1998 to the east of the summit craters. The overall 1998–2005 deformation pattern therefore forms an arcuate feature, whose geometry and kinematics are consistent with the head of a shallow flank deformation on the E summit of Etna. Similar deformation patterns have also been observed in analogue models of deforming volcanic cones. In this framework, the 2004–2005 eruption was possibly induced by a dike resulting from the intersection of this incipient fracture system with the SE Crater. A significant acceleration of this flank deformation may be induced by any magmatic involvement. The central conduit of the volcano is presently open, constantly buffering any increase in magmatic pressure and any hazardous consequence can be expected to be limited. A more hazardous scenario may be considered with a partial or total closing of the central conduit. In this case, magmatic overpressure within the central conduit may enhance the collapse of the upper eastern flank, triggering an explosive eruption associated with a landslide reaching the eastern lower slope of the volcano.

Description: Published

Description: 195–206

Description: reserved

Description: After the 2002 earthquakes, that struck the southern Italy provinces of Campobasso (Molise) and Foggia (Apulia), the safety assessment of buildings has allowed to evaluate, for different building typologies, the damage level caused by the seismic event; in particular, the survey of the damaged cultural heritage was carried out by the Task Cultural Heritage of the Mixed Operating Centre (COM) in Larino (a village in the epicentral area), coordinated by the “Working Group for the Safeguard of the Cultural Heritage from Natural Risks” (Italy’s Gazzetta Ufficiale n. 116, 21 May 2001 - PCM-DPC Decree, 3 May 2001)”. For this survey activity, the churches were investigated with a specific form proposed by the same Working Group (Ministerial Decree n. 133, 23th January 2001), adopting different forms for other kinds of buildings. The surveyors were organized in teams, called NOPSA (Nuclei Operativi Patrimonio Storico Artistico), composed by officials of the Regional board of the Ministry of Cultural Heritage and Environmental Conservation (architects and art historians), an engineer and a Fire Brigade technician. The first phase of the safety assessment has been developed on the basis of the warnings received by the Larino COM, and most of the surveyed buildings were churches. The damage assessment of public or private buildings began, initially, near the earthquake epicentre (area 1 - IMCS between 6 and 8.5) and subsequently was carried out for all the villages from which inspection requests arrived. At the same time a vulnerability survey was carried out for the churches, using the II level form (Lagomarsino et al., 2004) proposed in the SAVE Project (“Updated Tools for the Seismic Vulnerability Evaluation of the Italian Real Estate and of Urban Systems” – http://gndt.ingv.it). The damage and vulnerability survey has allowed to verify and optimize the procedures for damage assessment immediately after a seismic event (emergency phase) and to obtain useful indications for the reconstruction phase. On the whole 379 monumental buildings in 101 Molise villages and 207 monumental buildings in 44 Apulia villages were investigated. Figure 1 shows the number of monumental buildings surveyed after the earthquakes for each Molise village, subdividing the region according to the seismic classification proposed by the recent Italian Seismic Code (OPCM n. 3274, 2003 – http://zonesismiche.mi.ingv.it).

Description: Unpublished

Description: First European Conference on Earthquake Engineering and Seismology (a joint event of the 13th ECEE & 30th General Assembly of the ESC) Geneva, Switzerland, 3-8 September 2006 Paper Number: 656

Description: open

Description: Earthquake Early Warning Systems (EEWS), based on real-time prediction of ground motion or structural response measures, may play a role in reducing vulnerability and/or exposition of buildings and lifelines. In fact, recently seismologists developed efficient methods for rapid estimation of event features by means of limited information of the P-waves. Then, when an event is occurring, probabilistic distributions of magnitude and source-to-site distance are available and the prediction of the ground motion at the site, conditioned to the seismic network measures, may be performed in analogy with the Probabilistic Seismic Hazard Analysis (PSHA). Consequently the structural performance may be obtained by the Probabilistic Seismic Demand Analysis (PSDA), and used for real-time risk management purposes. However, such prediction is performed in very uncertain conditions which have to be taken into proper account to limit false and missed alarms. In the present study, real-time risk analysis for early warning purposes is discussed. The magnitude estimation is performed via the Bayesian approach, while the earthquake localization is based on the Voronoi cells. To test the procedure it was applied, by simulation, to the EEWS under development in the Campanian region (southern Italy). The results lead to the conclusion that the PSHA, conditioned to the EEWS, correctly predicts the hazard at the site and that the false/missed alarm probabilities may be controlled by set up of an appropriate decisional rule and alarm threshold.

Description: Published

Description: open

Description: The westernmost part of the Gulf of Corinth (Greece) is an area of very fast extension (~15 mm/yr according to geodetic measurements) and active normal faulting, accompanied by intense coastal uplift and high seismicity. This study presents geomorphic and biological evidence of Holocene coastal uplift at the western extremity of the Gulf, where such evidence was previously unknown. Narrow shore platforms (benches) and rare notches occur mainly on Holocene littoral conglomerates of uplifting small fan deltas. They are perhaps the only primary paleoseismic evidence likely to provide information on earthquake recurrence at coastal faults in the specific part of the Rift system, whereas dated marine fauna can provide constraints on average Holocene coastal uplift rate. The types of geomorphic and biological evidence identified are not ideal, and there are limitations and pitfalls involved in their evaluation. In a first approach, 5 uplifted paleoshorelines may be indentified, at 0.4- 0.7, 1.0-1.3, 1.4-1.7, 2.0-2.3 and 2.8-3.4 m a.m.s.l. They probably formed after 1728 or 2250 Cal. B.P. (depending on the marine reservoir correction used in the calibration of measured radiocarbon ages). A most conservative estimate for the average coastal uplift rate during the Late Holocene is 1.6 or 1.9 mm/yr minimum (with different amounts of reservoir correction). Part of the obtained radiocarbon ages of Lithophaga sp. allows for much higher Holocene uplift rates, of the order of 3-4 mm/yr, which cannot be discarded given that similar figures exist in the bibliography on Holocene and Pleistocene uplift at neighbouring areas. They should best be cross-checked by further studies though. That the identified paleoshoreline record corresponds to episodes of coastal uplift only, cannot be demonstrated beyond all doubt by independent evidence, but it appears the most likely interpretation, given the geological and active-tectonic context and, what is known about eustatic sea-level fluctuations in the Mediterranean. Proving that the documented uplifts were abrupt (i.e., arguably coseismic), is equally difficult, but reasonably expected and rather probable. Five earthquakes in the last ca. 2000 yrs on the coastal fault zone responsible for the uplift, compare well with historical seismicity and the results of recent on-fault paleoseismological studies at the nearby Eliki fault zone. Exact amounts of coseismic uplift cannot be determined precisely, unless the rate of uniform ("regional") non-seismic uplift of Northern Peloponnesus at the specific part of the Corinth Rift is somehow constrained.

Description: EU project 3HAZ-Corinth

Description: Published

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: open

Description: Prior to 2003 the Italian building code, established in 1974, was mostly based on working stress design. The zonation that guided its application was made up in 1981 using a semi-quantitative, mainly seismological approach; it was enforced in 1984 and left about 2/3 of the territory without seismic provisions. In 1998 a new zonation was proposed but never adopted. The 2002 Mw5.7 earthquake in Molise (Southern Italy) caused the collapse of a school and the death of 26 children. The school was built in an area where seismic provisions were not applied, although the zonation proposed in 1998 assigned it to the second zone. The earthquake triggered a process that led in a few months to a new set of seismic provisions

Description: Unpublished

Description: San Francisco

Description: open

Description: Published

Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce

Description: open

Description: After the 2002 Molise earthquake, a wide survey of the damage and the seismic vulnerability of the churches was carried out, using specific forms extensively tested and recently acknowledged at a national scale (G.U. 07/03/2006). This approach has allowed one to compare the observed and the expected medium damage, calculated through vulnerability curves correlated to the specific form used. This comparison has enabled to evaluate inhomogeneous values in some cases, pointing out how the surveyed damage could not be put down just to a structural lack of the building. Studying the sites morphology for the churches located on the ridges, it was observed a damage level always greater than expected. To study the influence of the local amplification phenomena due to the topography, it has been analyzed some churches damaged by the Appennino Abruzzese (1984) and Molise (2002) earthquakes. These churches are located on the ridges top, with slope in-clination alfa≥15°, height H≥30m and characterized by homogeneous lithological subsoil, almost to consider it having an elastic behavior under dynamical stress. Taking into account this hazard increase inside a vulnerability analyses (based on a macroseismic or a mechanical approach), it has been proposed a double approach, validated through local seismic response (RSL) modeling of the ground (estimation of amplification factors and of elastic response spectra) and through the seismic response of the macroelements, damaged by the reference earth-quake (linear and not-linear kinematic analysis). Through the vulnerability analysis based of the macroseismic approach, the influence of the site morphology on the building behavior has been preliminary defined by a vulnerability modifier (deltaVml), that represents an additional parameter to reach the equivalent value between the surveyed and the expected damage. The study of the amplification effects has been performed using the BEM numerical analysis; the results are represented by the amplification factors (Fa), defined as the ratio between the spectral intensity of output and input, considering the range period of 0.1s-0.5s, and the corresponding elas-tic response spectra: they confirm the results of the macroseismic approach. Considering the mechanical approach, two churches have been examined in detail (S Pietro in Vincoli at Castellino del Biferno and S. Michele Arcangelo at Campolieto): the kinematic analyses have been performed applied the calculated amplified and not-amplified response spectra (considering the earthquake 2002) and the design response spectrum. The analyses show that the results obtained applying the calculated amplified response spectrum are better correlated to the surveyed damage of the churches than the results obtained applying the not-amplified response spectrum.

Description: Published

Description: Pisa, Italia

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: The damage and vulnerability survey of the monumental buildings, damaged by the 2002 earthquake in the Molise Region, has allowed singling out of a correlation between the observed damage of the churches and their morphological site conditions. The vulnerability model connected to the survey methodology provides an evaluation of the expected mean damage. Comparison with the observed damage determined the introduction of a local morphological behaviour modifier, able to take into account the vulnerability increase due to the site effects. In order to validate the previous results, a numerical 2-D analysis of the seismic local response has been performed. In particular, a numerical code, working with boundary elements, has been applied to the analyzed situations. The results, in terms of pseudo-acceleration response spectra and amplification factors, allow one to compare the numerical and the observed analyses. This comparison shows good agreement and allows one to find some correlations between the geometric characteristics of the sites, the values of the amplification coefficients and the damage mechanism activated.

Description: Published

Description: Thessaloniki, Greece

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: 4.2. Scenari e mappe di pericolosità sismica e danno

Description: open

Description: This study contributes paleoseismological data on the recent history of surface-rupturing earthquakes on the southern (main) branch of the North Anatolian fault zone (NAFZ, Turkey), west of the Bolu basin. We focused on the fault segment that ruptured during the 1967 Mudurnu Valley earthquake (Ms 7.1), which preceded the devastating earthquakes of 1999 in the sequence of westward-migrating NAFZ earthquakes since 1939. Geomorphological mapping was carried out in a search for trenching sites on the central part of the 22 July 1967 earthquake segment. In the absence of locations in sedimentary environments best suited for paleoseismological interpretation of faulted Holocene deposits, we trenched fluvial channel deposits at a terrace of the graveldominated Mudurnu River. The most conservative interpretation of the trench stratigraphy and faulting evidence suggests that at least one paleoearthquake (most probably two) occurred after A.D. 1693. The 1967 earthquake segment has ruptured at least once since the historical earthquake of A.D. 1668, which was previously considered to be a likely candidate for the penultimate event, and before 1967. It is not possible to confidently assign the penultimate event to one of the post A.D. 1693 historical earthquakes in the broader area around the Mudurnu Valley (e.g., the earthquake of A.D. 1719) because the historical data published so far do not provide conclusive information about when past ruptures of the Mudurnu Valley branch of the NAFZ (a secluded area) did or did not take place.

Description: European Community project RELIEF

Description: Published

Description: 1646-1661

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: partially_open

Description: The aim of this work is to produce a prototype of an Integrated Geographic Informative System designed to characterize the seismic vulnerability of the municipalities of the Benevento province. The developed GIS model algorithm is based on a systemic methodology which accounts for interactions among the several factors involved into the system. The implemented algorithm allows to estimate a vulnerability index, which in turn led to the creation of vulnerability maps. This System, which could be enriched with new thematic data will provides the basis for future researches in the field and make available to local decision-makers, agencies and community planners basic information to be used in managing the seismic risk.

Description: Published

Description: Centro Congressi Lingotto, Torino

Description: open

Description: Is compression across the northern Apennine fold-and-thrust system (Italy) still active? To address this question, we quantified the long-term rates of migration and shortening of the system along with the measurement errors. Our approach integrates structural geology, seismicity patterns, and statistical treatment of tectonic activity. On the basis of recently published surface and subsurface data, we found a migration rate of 8.85 ± 0.61 mm/yr. The inception age of individual fold structures follow closely this average rate, indicating that the system has been migrating at a constant rate for the past 17 Myr. Cumulative shortening of the system also increases linearly through time at 2.93 ± 0.31 mm/yr. The location of the youngest structures in the easternmost portion of the system coincides with a significant peak of seismic moment released by historical earthquakes. We conclude that not only these easternmost thrusts are still active, but also that they generate earthquakes.

Description: Regione Marche

Description: Published

Description: 462–468

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: partially_open

Description: For early-warning applications in particular, the reliability and efficiency of rapid scenario generation strongly depend on the availability of reliable strong ground-motion prediction tools. If shake maps are used to represent patterns of potential damage as a consequence of large earthquakes, attenuation relations are used as a tool for predicting peak ground-motion parameters and intensities. One of the limitations in the use of attenuation relations is that these have only rarely been retrieved from data collected in the same tectonic environment in which the prediction has to be performed. As a consequence, strong ground motion can result in underestimations or overestimations with respect to the recorded data. This also holds for Italy, and in particular for the Southern Apennines, due to limitations in the available databases, both in terms of distances and magnitude. Moreover, for “real-time” early-warning applications, it is important to have attenuation models for which the parameters can be easily upgraded when new data are collected, whether this has to be done during the earthquake rupture occurrence or in the post-event, when all the strong motion waveforms are available. Here we present a strong-motion attenuation relation for early-warning applications in the Campania region (Southern Apennines), Italy. The model has a classical analytical formulation, and its coefficients were retrieved from a synthetic strong-motion database created by using a stochastic approach. The input parameters for the simulation technique were obtained through the spectral analysis of waveforms of earthquakes recorded by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) network for a magnitude range Md (1.5,5.0) in the last fifteen years, and they have been extrapolated to cover a larger range. To validate the inferred relation, comparisons with two existing attenuation relations are presented. The results show that the calibration of the attenuation parameters, i.e., geometric spreading, quality factor Q, static stress drop values along with their uncertainties, are the main concern.

Description: Published

Description: 133-152

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: reserved

Description: In the framework of an ongoing project financed by the Campania Region, a prototype system for seismic early and post-event warning is being developed and tested, based on a dense, wide dynamic seismic network (ISNet) and under installation in the Apennine belt region. This paper reports the characteristics of the seismic network, focussing on the required technological innovation of the different seismic network components (data-logger, sensors and data communication). To ensure a highly dynamic recording range, each station is equipped with two types of sensors: a strong-motion accelerometer and a velocimeter. Data acquisition at the seismic stations is performed using Osiris-6 model data-loggers made by Agecodagis. Each station is supplied with two (120 W) solar panels and two 130 Ah gel cell batteries, ensuring 72-h autonomy for the seismic and radio communication equipment. The site is also equipped with a GSM/GPRS programmable control/alarm system connected to several environmental sensors (door forcing, solar panel controller, battery, fire, etc) and through which the site status is known in real time. The data are stored locally on the hard-disk and, at the same time, continuously transmitted by the SeedLink protocol to local acquisition/analysis nodes (Local Control Center) via Wireless LAN bridge. At each LCC site runs a linux Earthworm system which stores and manages the acquired data stream. The real-time analysis system will perform event detection and localization based on triggers coming from data-loggers and parametric information coming from the other LCCs. Once an event is detected, the system will performs automatic magnitude and focal mechanism estimations. In the immediate post-event period, the RISSC performs shaking map calculations using parameters from the LCCs and/or data from the event database. The recorded earthquake data are stored into an event database, to be available for distribution and visualization for further off-line analyses. The seismic network will be completed in two stages: • Deployment of 30 seismic stations along the southern Apennine chain (to date almost completed) • Setting up a carrier-class radio communication system for fast and reliable data transmission, and installation of 10 additional seismic stations.

Description: Published

Description: 325 - 341

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: reserved

Description: The different geomorphological characteristics of the footwall and hanging wall sectors of Apennine active normal faults usually prevent the possibility to correlate synchronous geomorphological features across the fault and, therefore, to define the kinematic parameters. This is particularly evident in case of faults active during the Late Pleistocene – Holocene, evolving along mountain fronts in piedmont areas. Therefore, the use of geomorphological features such as paleolandscapes and chronologically constrained deposits of pre-Late Quaternary age can be useful for the definition of kinematic parameters. Following this approach we have analysed three cases in Central Apennines: 1) the Magnola Mts. normal fault, 2) the Mt. Morrone normal fault system and 3) the Norcia basin fault system. As for the cases at points 1 and 2, isochronous sub-horizontal breccias have been detected both in the hanging wall and in the footwall sectors of the Magnola Mts. fault and of the western fault segment of the Mt. Morrone fault system (made of two parallel fault branches) laying on an almost flat paleolandscape of older age, characterized by relict surfaces gently dipping towards the basin bottom, whose formation occurred close to the local base level. Since BOSI et alii (2003) attributed this kind of breccias to the Early Pleistocene, we can hypothesize that the formation of the fault-related slopes occurred subsequently to the Early Pleistocene. The vertical offset affecting the breccias can be quantified in 650 m for the Magnola Mts. fault and in 350 m for the Mt. Morrone western fault segment. Therefore, assuming that a reliable age for these deposits is 10.2 Ma, a slip rate ranging from 0.54 to 0.81 mm/yr can be estimated for the Magnola Mts. fault and ranging between 0.30 and 0.43 mm/yr for the Mt. Morrone western fault segment. As for the Norcia basin fault system, alluvial fans attributed to the Middle Pleistocene are geomorphologically embedded in almost flat relict surfaces carved into the limestone bedrock and detectable in the highest sectors of the relief representing the eastern basin border. Considering the difference in elevation between these paleosurfaces and the present bottom of the basin (assuming that surfaces or deposits synchronous to those present in the footwall are “contained” in the succession filling the depression), a minimum vertical offset due to the fault activity following the formation of the relict surfaces can be estimated in about 900 m. Moreover, considering that these relict surfaces may have an age ranging between the Middle Pliocene (after the end of the compressive tectonic phase) and the Middle Pleistocene, a minimum vertical fault slip rate ranging between 0.25 and 1.15 mm/yr can be estimated.

Description: Published

Description: 365-374

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: We calculated the impact on Southern Italy of a large set of tsunamis resulting from earthquakes generated by major fault zones of the Mediterranean Sea. Our approach merges updated knowledge on the regional tectonic setting and scenario-like calculations of expected tsunami impact. We selected three potential source zones located at short, intermediate and large distance from our target coastlines: the Southern Tyrrhenian thrust belt; the Tell-Atlas thrust belt; and the western Hellenic Arc. For each zone we determined a Maximum Credible Earthquake and described the geometry, kinematics and size of its associated Typical Fault. We then let the Typical Fault float along strike of its parent source zone and simulated all tsunamis it could trigger. Simulations are based on the solution of the nonlinear shallow water equations through a finite-difference technique. For each run we calculated the wave fields at desired simulation times and the maximum water elevation field, then produced travel-time maps and maximum wave-height profiles along the target coastlines. The results show a highly variable impact for tsunamis generated by the different source zones. For example, a large Hellenic Arc earthquake will produce a much higher tsunami wave (up to 5 m) than those of the other two source zones (up to 1.5 m). This implies that tsunami scenarios for Mediterranean Sea countries must necessarily be computed at the scale of the entire basin. Our work represents a pilot study for constructing a basin-wide tsunami scenario database to be used for tsunami hazard assessment and early warning.

Description: Italian Civil Defense; Project “Development of new technologies for the protection of the Italian territory from natural hazards” funded by the Italian Ministry of University and Research

Description: Published

Description: B01301

Description: 3.1. Fisica dei terremoti

Description: 3.2. Tettonica attiva

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: partially_open

Description: One of the main requirements by OPCM 3274 was the transparency of the PSH assessment (to be achieved through the publication of the procedure adopted and the data used) so that anyone would be able to verify the consistency of the results and follow the most updated state-of-the-art. In addition, OPCM 3519 stated that the seismic hazard data had to be made officially available through a dedicated website (http://zonesismiche.mi.ingv.it). The web site supplies the seismic hazard data expressed in terms of peak ground acceleration (ag) with 10% of exceedance probability in 50 years as well as their variability stated in terms of the 16th and 84th percentiles. In addition, the same website can supply even the scientific technical documentation as well as the input data used in such a project. As integration of these contents, a second web site (http://esse1.mi.ingv.it) has been developed with the aim to make available all the information about the organization of the S1 project (work program, tasks organization, list of the deliverables, progress state), underlying the most important results and for an immediate fruition by the project endusers. For this purpose a webGis tool has been carried out to visualize and query interactive hazard maps of the Italian territory, represented through various shaking parameters (values of peak ground acceleration and elastic response spectra for a given T period).

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: Vengono presentate nuove relazioni empiriche, definite per il territorio italiano, per la stima dell’intensità in un dato sito a partire da informazioni epicentrali o relative a località vicine. Queste relazioni, espresse in forma probabilistica e quindi direttamente utilizzabili per la stima della pericolosità sismica, condividono la stessa formalizzazione e la medesima base informativa. In particolare, sono state seguite tre diverse strategie: le prime due hanno portato alla definizione di una relazione di attenuazione per la stima dell’intensità al sito da dati epicentrali utilizzando una forma parametrica rispettivamente Gaussiana e Binomiale; la terza analisi è stata invece mirata a definire le modalità di “correzione” del valore locale di intensità, dedotto dalle informazioni epicentrali, con dati di risentimenti osservati in località vicine al sito in esame.

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 5.1. TTC - Banche dati e metodi macrosismici

Description: open

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: Unpublished

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: The last strong earthquake that occurred in the southern Apennines, the Irpinia earthquake on 23 November 1980 (M 6.9), was characterized by a complex rupture mechanism that ruptured three different faults (Bernard and Zollo 1989). This earthquake was well studied, and the quantity of data available has allowed a very detailed definition of the geometry and mechanisms of faults activated during this seismic event (Westaway and Jackson 1987; Pantosti and Valensise 1990). Even more than 20 years after the main event, the seismotectonic environment that contains the fault system on which the 1980 earthquake occurred shows continued background seismic activity including moderate-sized events such as the 1996 (M 5.1), 1991 (M 5.1) and 1990 (M 5.4) events. Moreover, the locations of the microearthquakes (taken from the database of the Istituto Nazionale di Geofisica e Vulcanologia, INGV) define an epicentral area with a geometry and extent surprisingly similar to that of the 1980 earthquake and its aftershocks (figure 1A). These simple observations suggest that it may be possible to study the preparation cycles of strong earthquakes on active faults by studying the microseismicity between seismic events. With this in mind, a seismic network of large dynamic range was planned and is now in an advanced phase of completion in the southern Apennines. Called ISNet (Irpinia Seismic Network), it is equipped with sensors that can record high-quality seismic signals from both small-magnitude and strong earthquakes, from which it will be possible to retrieve information about the rupture process and try to understand the scaling relationships between small and large events. Due to its high density, wide dynamic range, and advanced data-acquisition and data-transmission technologies, the network is being upgraded to become the core infrastructure of a prototype system for seismic early warning and rapid post-event ground-shaking evaluation in the Campania region, which has seismic hazard that ranks among the highest in Italy (Cinti et al. 2004). ISNet will be devoted to real-time estimation of earthquake location and magnitude and to measuring peak ground-motion parameters so as to provide rapid ground-shaking maps for the whole of the Campania region. The information provided by ISNet during the first seconds of a potentially damaging seismic event can be used to activate several types of security measures, such as the shutdown of critical systems and lifelines (Iervolino et al. 2006). The implementation of a modern seismic network involves many different research and technological aspects related to the development of sophisticated data management and processing. The communication systems need to rapidly generate useful, robust, and secure alert notifications. Here we provide a general technical and seismological overview of ISNet's complex architecture and implementation.

Description: Published

Description: 622-634

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: JCR Journal

Description: reserved

Description: The Eliki fault system dominates the landscape of the southwestern shore of the Gulf of Corinth, where rapid extension rates result in frequent earthquakes. These include an event in 373 BC that destroyed the city of Helike and a recent event in 1861. Uplifted Late Pleistocene marine terraces within the Eastern Eliki Fault footwall suggest revised slip rates of ∼3–5 mm yr−1, contributing ∼2–3 mm yr−1 geological extension to a net geodetic extension of ∼10–15 mm yr−1 across this part of the rift. Palaeoseismological trenches indicate two and possibly three earthquakes on the Eastern Eliki Fault in the last 1500 yr, including the 1861 earthquake. One trench (EET1A) reveals displaced stratigraphy, but the main fault trace is thought to lie further south beneath the Old National Road. Trench EET1A reveals liquefied sediments associated with an event between AD1460 and the present, which may be the 1861 event, and displacement during a second event in the interval AD 440–1410 or AD 1270–1640. A third earlier event identified by liquefaction occurred on the Eliki or a nearby fault in AD 440–1410. Using the 1861 and second event (most likely AD1270–1640), the interval between recent earthquakes is ∼200–600 yr. Suitable trench sites are rare in this region, compounded by human activity over several thousand years. Borehole and trench data indicate that the Kerynites river frequently flowed eastwards along the Eastern Eliki Fault during the last 20–40 kyr, possibly influenced by tectonic tilting from the Eliki and Aigion fault systems and natural channel avulsion.

Description: Published

Description: 154-166

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: Managua, capital of Nicaragua, is built on the shore of Lake Managua, within a densely faulted graben at a major discontinuity in the Central American volcanic chain. Shallow moderate earthquakes (Ms 6–6.2) ruptured faults with devastating effect at the heart of urban Managua in 1931 and 1972, and damaging earthquakes are cataloged in the earlier history of the surrounding region. The Aeropuerto fault is a major structure in the Managua Graben, but like other faults in this area its behavior is little understood. Paleoseismic investigations now suggest that the most recent large earthquake on this fault occurred sometime during the interval A.D. 1650–1810. An earlier earthquake on this fault occurred prior to A.D. 1390 and possibly around 2000 B.P. On the basis of stratigraphic correlations we estimate the ages of two shorelines associated with former high stands of Lake Managua to be less than 6.4 ka and approximately 2 ka, respectively. Deformation of these abandoned shorelines adjacent to the Aeropuerto fault implies a vertical slip rate of 0.3 to 0.9 mm/yr. Strikeslip movement on this fault is also expected, but no direct measurement could be performed. By comparison with faults of similar geometry in the Managua area that ruptured in 1931 and 1972, we suspect a left-lateral component of horizontal slip that is higher than the vertical one but less than 5 mm/yr. Additional data on slip rate and timing of paleoearthquakes are needed to better assess the Holocene behavior of the Managua faults and to investigate the influence of magmatic processes on the nature of faulting in the Managua Graben.

Description: Published

Description: 1694-1707

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: The source mechanisms responsible for large historical tsunamis that have struck eastern Sicily and southern Calabria are a topic of robust debate. We have compiled a database of historical coeval descriptions of three large tsunamis: 11 January 1693, 6 February 1783, and 28 December 1908. By using accounts of run-up and inundation and employing an approach proposed by Okal and Synolakis in 2004, we can provide discriminants to define the nature of the near-field tsunami sources (fault dislocation or landslide). Historical reports for the 1908 event describe affected localities, maximum runups, and inundation areas. However, for the 1693 and 1783 tsunamis, reports are limited to inundation and occasional run-up estimates. We calculate run-up values for these events using available relations between inundation and run-up. We employed the model of Okal and Synolakis to the obtained profiles of tsunami run-up along the inundated shorelines. The 1908 run-up data distribution confirms that the tsunami is compatible with a seismic dislocation source, whereas the 1783 data supports contemporary observations and recent offshore investigations suggesting that the tsunami was produced by an earthquake-triggered submarine landslide. Analysis of the 1693 event data suggests that the tsunami was generated during a tectonic event and thus a seismogenic source should be found offshore.

Description: Italian CIvil Protection INGV-DPC Agreement 2004-2006

Description: Published

Description: 2795-2805

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: partially_open

Description: È ormai ampiamente riconosciuto che la risposta sismica locale ha una sensibile influenza su distribuzione ed amplificazione dello scuotimento sismico e, conseguentemente, sul danneggiamento indotto dai terremoti. Nel lavoro di tesi, dal titolo “Analisi della Risposta Sismica Locale di San Giuliano di Puglia”, il candidato presenta uno studio molto ampio ed approfondito della risposta sismica del centro urbano che rappresenta finora la case history più documentata e significativa in Italia. Il lavoro di ricerca è inquadrato nel “Progetto S3 - Scenari di scuotimento in aree di interesse prioritario e/o strategico” promosso dall’Istituto Nazionale di Geofisica e Vulcanologia (INGV) per conto del Dipartimento della Protezione Civile (DPC), coordinato dalla Dr.ssa Francesca Pacor (INGV, Milano) e dal Prof. Marco Mucciarelli (Università della Basilicata). Il Progetto di ricerca si pone come obiettivo generale l’analisi di scenari di scuotimento e di danno in alcune aree italiane, nel caso di accadimento del terremoto massimo credibile (Maximum Credible Earthquake). Tra le aree di validazione è individuata quella di San Giuliano di Puglia, particolarmente danneggiato dalla sequenza sismica del Molise nel 2002, il cui vento principale (31 ottobre) è caratterizzato da una magnitudo momento pari a 5.8. Nell’area sono presenti diversi centri abitati, tra i quali San Giuliano di Puglia che, sebbene non fosse meno distante di altri dagli epicentri, è stato quello maggiormente danneggiato. Infatti, dopo gli eventi sismici, a San Giuliano di Puglia è stato osservato un grado di danneggiamento pari al VIII-IX grado sulla base della scala MCS, mentre negli altri Comuni la stima è stata al limite pari al VII (Stucchi et al., 2007). Il motivo di tale discrepanza è da ricercarsi negli importanti fenomeni di amplificazione sismica locale che hanno interessato le aree di più recente costruzione di San Giuliano di Puglia; queste sono state edificate, a partire dagli anni ’40, su un deposito di marne argillose di spessore pari ad alcune centinaia di metri. Tale deposito è a contatto con una formazione flyschoide, affiorante al di sotto del nucleo originario dell’abitato, dove è stato osservato un danneggiamento di grado inferiore. Dopo un’analisi preliminare della letteratura con riferimento a casi di studio nazionali che internazionali di carattere simile, la prima parte del lavoro di ricerca è dedicata allo studio della pericolosità sismica del sito, con riferimento a dati storici e, soprattutto, strumentali, acquisiti nel corso della recente sequenza. A tal fine, sono state analizzate le registrazioni della rete accelerometrica mobile installata da DPC nel centro urbano di San Giuliano di Puglia; tali registrazioni, interpretate in termini di fattori di amplificazione e rapporti spettrali, hanno permesso di verificare amplificazioni sismiche molto elevate nell’intero campo di frequenze in cui può essere ascritto il patrimonio edilizio del paese. Nell’ambito del Task 1 del Progetto S3, sono stati esaminati circa 2000 sismogrammi registrati dalla RAN (Rete Accelerometrica Nazionale) e dalle reti mobili installate nell’area epicentrale alcuni giorni dopo il mainshock. Queste analisi hanno consentito la calibrazione di leggi di attenuazione specifiche per l’area di studio (Luzi et al., 2006) e la simulazione numerica dell’evento del 31 ottobre (Franceschina et al., 2006). La seconda parte della tesi ha riguardato la definizione del modello geologico di sottosuolo per l’analisi di risposta sismica locale. I diversi studi geologici in merito (cfr. Baranello et al., 2003; Melidoro, 2004 e Guerricchio, 2005; Giaccio et al., 2004; Strollo et al., 2006) suggeriscono diverse ipotesi in merito alla morfologia profonda delle formazioni geologiche principali, il flysch di Faeto e le marne argillose di Toppo Capuana. Queste corrispondono, in buona sostanza, a diversi andamenti in profondità del contatto tra formazione argillo-marnosa ed il substrato flyschoide, identificati con altrettanti modelli geometrici di sottosuolo (basin, wedge, anvil). Tale fattore risulta fortemente influente sulla risposta sismica locale alle basse frequenze. Le ipotesi sono state verificate con riferimento ai risultati delle indagini geofisiche profonde, eseguite nell’area di San Giuliano di Puglia nell’ambito del Progetto S3; queste sono consistite in 3 inversioni tomografiche geoelettriche (Piscitelli, 2007), una campagna gravimetrica di dettaglio (Palmieri et al., 2006) e 2 linee sismiche a riflessione (Böhm, 2007). Sempre nell’ambito del Progetto S3, i risultati di queste indagini hanno consentito la costruzione di un modello geologico strutturale 3D dell’area (Caputo et al., 2007). La terza parte ha riguardato la definizione del modello geotecnico di sottosuolo per l’analisi di risposta sismica locale. Si è provveduto alla raccolta ed analisi di tutte le indagini geotecniche eseguite nel centro abitato, con particolare riferimento alla campagna del DPC per conto della Procura di Larino (Baranello et al., 2003), che ha consentito un’adeguata caratterizzazione geotecnica dell’unità argillosa. Durante questa campagna, nel 2003, sono state eseguite 11 prove down-hole e 3 prove cross-hole spinte anche oltre i 30 m di profondità, e, sui campioni di terreno prelevati, diversi laboratori hanno eseguito, oltre alle usuali prove di classificazione, numerose prove di compressione edometrica e isotropa, triassiali non drenate e di taglio torsionale ciclico e dinamico (Silvestri et al., 2006). I parametri meccanici attribuiti all’unità flyschoide provengono invece un’unica prova down-hole, eseguita nel corso della vasta campagna geognostica (2004-5) per la ricostruzione del paese. Il gran numero di sondaggi nell’intero centro urbano ha permesso una descrizione molto dettagliata della stratigrafia delle marne argillose di Toppo Capuana, il cui spessore più superficiale (mediamente fino a circa 10 m di profondità), si presenta caratterizzato da un alto grado di weathering e da un sensibile contrasto di impedenza sismica con le sottostanti argille intatte. L’eterogeneità della stratigrafia in direzione verticale ed orizzontale è stata rappresentata con diversi livelli di dettaglio, cioè assimilando la formazione superficiale ad un materiale omogeneo, oppure suddiviso in due strati, con spessori costanti oppure considerandone la variabilità con criteri geostatistici; tale approccio ha permesso di valutare l’influenza sull’amplificazione delle frequenze medio alte (oltre i 5 Hz) del dettaglio stratigrafico nella caratterizzazione dell’unità argillosa degradata. Nella quarta parte, il candidato presenta i risultati delle simulazioni numeriche 2D agli elementi finiti (codice QUAD4M), eseguite allo scopo di confrontare le diverse ipotesi formulate sull’andamento del bedrock e sulla stratigrafia superficiale, e validarle in base alle registrazioni strumentali. Come moti di riferimento sono state assunte due registrazioni della rete accelerometrica mobile di San Giuliano di Puglia, effettuate sulla formazione flyschoide nel corso degli aftershocks occorsi il 12 novembre (M=5.2) ed il 2 dicembre (M=4.0). Lo scuotimento in superficie simulato dalla modellazione numerica è confrontato, in termini sia di parametri sintetici del moto (accelerazioni di picco, intensità di Housner), sia di spettri di risposta, con le rispettive registrazioni eseguite alla superficie dell’unità argillosa e del flysch. L’ultima parte della tesi descrive lo scenario di scuotimento e di danno nel centro abitato indotto dal mainshock del 31 ottobre. Le simulazioni numeriche dello scuotimento sono state eseguite sui modelli di sottosuolo 2D elaborati lungo una sezione che attraversa l’asse longitudinale del centro urbano e validati nella fase precedente. I parametri del moto sono stati confrontati sia con quelli ottenuti tramite analisi 3D con il metodo degli elementi pseudo-spettrali (FPSM) lungo la medesima sezione (Klin e Priolo, 2007), e raffrontati con le amplificazioni registrate dalle stazioni accelerometriche mobili di San Giuliano di Puglia durante le scosse di assestamento. Le distribuzioni del danno corrispondenti alle analisi 2D e 3D sono state elaborate a partire dallo scuotimento, attraverso una correlazione tra l’intensità di Housner e quella macrosismica, espressa secondo la scala MCS (Mucciarelli et al., 2007). Gli scenari di danno così ottenuti hanno mostrato un buon accordo con quello osservato all’indomani della crisi sismica da Dolce et al. (2004). I risultati degli studi interdisciplinari sul centro urbano di San Giuliano di Puglia hanno quindi rappresentato una favorevole occasione per mettere a punto metodologie di previsione numerica di risposta sismica locale, evidenziandone la sensibilità a fattori geometrici e meccanici. La ricerca ha offerto inoltre la possibilità di esprimere i risultati di tali simulazioni in termini di grandezze significative per la rappresentazione del danno ai manufatti.

Description: Università della Calabria (Prof. Francesco Silvestri) - DPC-INGV (Progetto S3, 2004-2006 - coordinatori: Dott.ssa F. Pacor e Prof. M. Mucciarelli)

Description: Unpublished

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: Tra tutte le strutture portuali censite all’interno del Programma di Ricerca “Progettazione sismica di strutture portuali marine” si sceglie il porto di Ancona come caso particolare per una valutazione deterministica di pericolosità e rischio sismico. Ancona, infatti, essendo uno dei principali porti in Italia per importanza del volume di scambio, costituisce un caso rappresentativo della situazione italiana per aree a medio-alta pericolosità sismica. Attraverso lo studio del caso di Ancona si é cercato di definire un procedimento per la valutazione del rischio generalmente riproducibile. Infatti, affinché questo metodo di investigazione sia facilmente replicabile per tutti i porti italiani, esso viene articolato a diversi livelli di dettaglio, in funzione dei dati e delle risorse disponibili. Particolare attenzione è stata posta nel valutare l’influenza sulla stima del danno per i diversi livelli di scuotimento. La ricerca viene sviluppata secondo i seguenti punti: i) scelta dell’evento (o degli eventi) di riferimento; ii) stima degli scenari di scuotimento con riferimento a suolo rigido, attraverso valutazioni empiriche e simulazioni avanzate, e valutazione della variabilità dei parametri del moto; iii) valutazione degli effetti di amplificazione geologica, stima del potenziale di liquefazione e dei cedimenti del terreno; iv) individuazione dei fattori per la valutazione del rischio (valutazione combinata di pericolosità , esposizione e vulnerabilità degli elementi) e infine v) valutazione del danno atteso.

Description: Eucentre, DPC.

Description: Published

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: In this work the results of a quick microtremor survey performed in the municipalities situated in the epicentre area of the Ml 5.2 2004 Salò earthquake (North Italy) are presented. The aim of this study is to understand if the large amount of damage caused by the event (about 215 millions of euros only in the areas near to the epicenter) is correlated more to the local surface geology conditions or to the vulnerability of ancient Italian historical centers. A preliminary seismic zonation was carried out in 5 villages including about 30 measurements of microtremors analysed by the Nakamura technique (hereinafter HVNR). The points of measurement were carefully selected considering sites located both near damaged buildings and over different local geology conditions (alluvium deposits, fluvial-glacial deposits, debris fans and rock). In order to strengthen the HVNR results and to evaluate the reliability of the Nakamura analysis, a comparison with spectral ratios calculated on earthquakes (hereinafter HVSR) recorded at the strong motion station of Vobarno was made. In general, the outcomes of the survey highlight a possible correlation between local geology conditions and ground motion amplification for different frequency bands. In order to check if this evidence is linked with the damage, a series of macroseismic intensities values were collected for different zones of the investigated area, and a non parametric correlation approach was used to establish a possible correlation between damage and ground motion amplification for selected frequency bands. The results show, from a statistical point of view, that in the area surrounding the epicenter of the 24 November 2004 mainshock, the damage pattern is not strongly dependent upon the local surface geology but more correlated to the low quality of the civil structures present in the area, including old buildings of the last century.

Description: Submitted

Description: 12-36

Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale

Description: JCR Journal

Description: open

Description: We designed a new seismic source model for Italy to be used as an input for country-wide probabilistic seismic hazard assessment (PSHA) in the frame of the compilation of a new national reference map. We started off by reviewing existing models available for Italy and for other European countries, then discussed the main open issues in the current practice of seismogenic zoning. The new model, termed ZS9, is largely based on data collected in the past 10 years, including historical earthquakes and instrumental seismicity, active faults and their seismogenic potential, and seismotectonic evidence from recent earthquakes. This information allowed us to propose new interpretations for poorly understood areas where the new data are in conflict with assumptions made in designing the previous and widely used model ZS4. ZS9 is made out of 36 zones where earthquakes with Mw 〉= 5 are expected. It also assumes that earthquakes with Mw up to 5 may occur anywhere outside the seismogenic zones, although the associated probability is rather low. Special care was taken to ensure that each zone sampled a large enough number of earthquakes so that we could compute reliable earthquake production rates. Although it was drawn following criteria that are standard practice in PSHA, ZS9 is also innovative in that every zone is characterised also by its mean seismogenic depth (the depth of the crustal volume that will presumably release future earthquakes) and predominant focal mechanism (their most likely rupture mechanism). These properties were determined using instrumental data, and only in a limited number of cases we resorted to geologic constraints and expert judgment to cope with lack of data or conflicting indications. These attributes allow ZS9 to be used with more accurate regionalized depth-dependent attenuation relations, and are ultimately expected to increase significantly the reliability of seismic hazard estimates.

Description: Published

Description: 85-108

Description: 3.2. Tettonica attiva

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: reserved

Description: An evaluation of the actual reliability of probabilistic seismic hazard (PSH) assessments, provided by existing numerical techniques, is mandatory to orientate new researches and improvements. Two procedures devoted to this task are proposed, which are based on the comparison of the hazard estimates with empirical observations (e.g. strong-motion data). These procedures have been applied to the estimates provided by the methodology adopted for most recent seismic hazard evaluations in Italy. The analysis shows that a significant mismatch exists between peak ground acceleration values characterized by an exceedence probability of 10 per cent in 30 yr and what has actually been observed at 68 accelerometric stations located on stiff soil, where continuous seismicity monitoring has been performed in the last 30 yr. Although this finding should be considered with caution, it suggests that a future re-examination of the adopted PSH computational model could be useful to avoid possible underestimates of seismic hazard in Italy.

Description: Published

Description: 1088–1094

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: reserved

Description: Viene descritto il percorso metodologico adottato per gli studi di microzonazione sismica nella provincia di Campobasso, colpita dal terremoto del 2002. Questi studi hanno permesso una completa ed omogenea caratterizzazione della geologia, della geomorfologia e delle caratteristiche geotecniche dei terreni di tutti i centri urbani esistenti. Per valutare le azioni sismiche di progetto, da utilizzare nella successiva fase della ricostruzione, sono stati calcolati i fattori di amplificazione sismica locale per aree omogenee del centro abitato. Il prodotto finale dell'attività è stata la redazione delle mappe di microzonazione sismica dei centri abitati.

Description: Published

Description: 293

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: reserved

Description: In this study, we compute the effect of stress change due to previous historical earthquakes on the probability of occurrence of future earthquakes on neighboring faults. Following a methodology developed in the last decade, we start from the estimate of the probability of occurrence in the next 50 years for a characteristic earthquake on known seismogenic structures, based on a time-dependent renewal model. Then a physical model for the Coulomb stress change caused by previous earthquakes on these structures is applied. The influence of this stress change on the occurrence rate of characteristic earthquakes is computed, taking into account both permanent (clock advance) and temporary (rate-and-state) perturbations. We apply this method to the computation of earthquake hazard of the main seismogenic structures recognized in the Central and Southern Apennines region, for which both historical and paleoseismological data are available. This study provides the opportunity of reviewing the problems connected with the estimate of the parameters of a renewal model in case of characteristic earthquakes characterized by return times longer than the time spanned by the available catalogues and the applicability of the concept of characteristic earthquake itself. The results show that the estimated effect of earthquake interaction in this region is small compared with the uncertainties affecting the statistical model used for the basic time-dependent hazard assessment.

Description: Published

Description: B08313

Description: 3.1. Fisica dei terremoti

Description: 3.2. Tettonica attiva

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: reserved

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Unpublished

Description: 3.2. Tettonica attiva

Description: open

Description: The outermost, NE-verging fronts of the Northern Apennines (Italy) are overlain by a thick syntectonic sedimentary wedge filling up the basin beneath the Po Plain. Due to fast sedimentation rates and comparatively low tectonic rates, the fronts are generally buried. Evidence for their activity includes scattered historical and instrumental earthquakes and drainage anomalies controlled by growing buried anticlines. The largest earthquakes, up to Mw 5.8, are associated with active compression with a GPS-documented shortening rate 〈1 mm/a. We used geological, structural and morphotectonic data to draw a N-S–striking section between Bologna and Ferrara, aimed at analyzing whether and how the deformation is partitioned among the frontal thrusts of the Northern Apennines and identifying the potential sources of damaging earthquakes. We pointed out active anticlines based on the correspondence among drainage anomalies, historical seismicity and buried ramps. We also analyzed the evolution of the Plio-Quaternary deformation by modeling in a sandbox the geometry, kinematics and growth patterns of the thrust fronts. Our results (i) confirm that some of the main Quaternary thrusts are still active and (ii) highlight the partitioning of deformation in the overlap zones. We note that the extent and location of some of the active thrusts are compatible with the location and size of the main historical earthquakes and discuss the hypothesis that they may correspond to their causative seismogenic faults.

Description: Published

Description: 605-613

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: The fundamental goal of this chapter is to provide a summary of the seismotectonics of the Messina Strait with special reference to the 28th December 1908 earthquake, the bridge Design Earthquake. We summarize what is known about the earthquake, describe the source model that has been used for assessing the bridge design seismic action (see Section 5.2. Seismic hazard and design earthquakes) and discuss some short- and long- term implications of tectonic activity in the area.

Description: Published

Description: 2-17

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: reserved

Description: This document illustrates in details the raw structure of the Database of Individual Seismogenic Sources, version 3 [Basili et al., 2008; http://diss.rm.ingv.it/diss/] - hereinafter referred to as the Database – and is dedicated at instructing any potential contributor, outside the DISS Working Group, on how to populate it with new seismogenic sources. It is worth of notice that the primary purpose of the Database is to provide a seismogenic source model at regional scale. It is hence usually populated by filling in large regions at once, not record by record.

Description: INGV, Roma1

Description: Published

Description: 3.2. Tettonica attiva

Description: open

Description: Seismogenic stress orientations are estimated in the lithosphere of Sicily by inversion of 131 local earthquake focal mechanisms (FMs) selected from the literature. An average misfit F = 14.5° between stress tensor and FMs indicates that the entire set of earthquakes is generated by a highly heterogeneous stress field. Detailed analysis of stress tensors and related earthquake misfits obtained for tens of subsets based on spatial separation of data allowed us to identify two main stress domains in the study region: (i) a compressional domain, including Etna, western Sicily and the southern Tyrrhenian sea offshore Sicily, where the σ1 orientation roughly changes from NW–SE in the Etna area and western Sicily to NNE–SSW at the northeastern edge of the domain (Eolian Islands) and (ii) an extensional domain in northeastern Sicily between the Eolian Islands and Etna, where σ3 is oriented analogously to previously estimated in the easterly confining extensional area of the Messina Straits. General agreement is found between this stress pattern and the GPS crustal displacement vectors reported in the most recent literature for the study region. Moreover, stress inversion enables us to locate the extensional domain more accurately than the presently available GPS data. Finally, the stress orientations estimated in the southern and western sectors of the study area (Etna and western Sicily on and offshore) match well with the displacement fields predicted for Sicily by large-scale models of plate motion, conversely a mismatch is observed in the northeastern sector (Eolian Islands and northeastern Sicily). We suggest that the joint action of Africa–Eurasia convergence and Ionian subduction trench retreat (rollback of the subducting slab) may explain the stress pattern detected in Sicily in the present study. Work for computation of a finite-element regional geodynamic model based on geophysical and geological data collected over the last few years has recently started with the purpose of quantitatively checking this hypothesis.

Description: Published

Description: partially_open

Description: An anisotropic attenuation law, based on an anisotropic characterization of intensity distribution for seismogenic zones, is proposed. This approach, that distinguishes itself for its consistency to the observed data, initially reconfigured by filtering procedures, is particularly suitable for seismic hazard evaluation.

Description: Published

Description: 707-714

Description: partially_open

Description: The Pollino Range area represents the most prominent gap in seismicity within the southern Apennines. Geomorphic and trenching investigations along the Castrovillari fault indicate that this normal fault is a major seismogenic fault within the southern part of this gap. At least four surface-faulting earthquakes have occurred on this fault since late Pleistocene age. Radiocarbon dating coupled with historical consideration set the time of the most recent earthquake as most likely to be between 530 A.D. and 900 A.D., with the possible widest interval of 530–1100 A.D. No evidence for this event has been found in the historical records, although its age interval falls within the time spanned by the seismic catalogues. Slip per event ranges between 0.5 and 1.6 m, with a minimum rupture length of 13 km. These values suggest a M 6.5–7.0 for the paleoearthquakes. The minimum long-term vertical slip rate obtained from displaced geomorphic features is of 0.2–0.5 mm/yr. A vertical slip-rate of about 1 mm/yr is also inferred from trenching data. The inter-event interval obtained from trench data ranges between 940 and 7760 years (with the young part of the interval possibly more representative; roughly 940–3000 years). The time elapsed since the most recent earthquake ranges between a minimum of 900–1100 and a maximum of 1470 years. The seismic behavior of this fault appears to be consistent with that of other major seismogenic faults of the central-southern Apennines. The Pollino case highlights the fact that geological investigations represent a potentially useful technique to characterize the seismic hazard of ‘silent’ areas for which adequate historical and seismological data record are not available.

Description: Published

Description: 199-217

Description: N/A or not JCR

Description: reserved

Description: A digitization has been performed of all volcanic rock fragments, main thrust fronts and fold axes from the 'Synthetic Structural Kinematic Map' as well as of all intrasedimentary magnetic bodies from the map of Cassano et al. These two maps complement each other, and the buried magnetized bodies fill the gaps of volcanic rocks in various regions e.g. in Tuscany. Some other major gaps can be found along the Northern Apennines, the Central and Southern Apennines and the Calabrian arc. A comparison of a map representing the 'Log C - seismic macrozonation index' to the pattern of all volcanic rocks, reveals that more seismic energy is released in those areas where volcanic rocks are absent or where their continuity in space is interrupted. Furthermore seismic activity is inhibited in those areas where minimum values of Bouguer anomalies are recorded.

Description: Published

Description: 165-181

Description: reserved

Description: - Many people in this room are geologists (in a broad sense!) - Most of them are (directly or indirectly) involved in Seismic Hazard Assessment at national or local level - Geologists are indeed forcing a revolution in SHA practice. Let’s keep up the good work! - I will be supplying some “food for thought” for an ever-growing community that sometimes needs to look back and recalibrate its efforts - They are here because their work relates somehow to Earthquake Geology

Description: Unpublished

Description: Vienna, Austria, 02-07 april 2006

Description: open

Description: Short commentary sent to the APRE commission for the Latin American - Europe scientific cooperation

Description: Analysis of a relocated hypocentres database and of a global volcanic eruptions catalogue has made clear that the South American Pacific margin is a site of peculiar phenomena and related geophysical events. The already known maximum rate of deep earthquakes, the expected mean recurrence time of extreme magnitude earthquakes of a few tens of years, and the closeness of the region to the Nazca triple point – i.e. the region with the maximum rate of sea floor expansion – mean that the Andean margin deserves priority in preparing stable geophysical instrument arrays in anticipation of the next great earthquake, with the aim of increasing our understanding of the real nature of earthquakes, of the real geodynamics of active margins, and of global geodynamics and tectonics

Description: Published

Description: 60-68

Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive

Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive

Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani

Description: 3.1. Fisica dei terremoti

Description: 3.2. Tettonica attiva

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: 3.6. Fisica del vulcanismo

Description: 4.3. TTC - Scenari di pericolosità vulcanica

Description: 5.2. TTC - Banche dati di sismologia strumentale

Description: 5.6. Consulenze nell'ambito di trattati internazionali

Description: N/A or not JCR

Description: open

Description: A geological cross-section, oriented about N80°E and crossing the Colfiorito area, struck by the 1997-98 Umbria-Marche earthquaks has been built up, integrating surface geological data (field mapping, 1:10.000 scale) and the interpretation of a seismic reflection profile, kindly provided by Eni-Agip Division. The section extends from the Umbra Valley Basin, west of Assisi, through the M.Subasio anticline, the Topino valley syncline and the “Inner Ridge” of the Umbria- Marche Apennines; the latter consists of seven box-shaped anticlines, with a wavelength of about 3 km. The seismic profile shows that at least the shallower part of the Basement is involved in the compressional structures, forming three steps stacked at depths ranging from 5 to 8 km, located between the M.Subasio anticline and the “Inner Ridge” of the Umbria-Marche Apennines. The interpreted section also allows a reconstruction of the deep geometry of the presumably active faults bounding the Colfiorito, Annifo and S.Martino basins. These faults trend N140°+_10°, dip towards SW at ~40°, to a depth of 8-9 km. The faults geometry is comparable with that suggested by the seismological data (focal mechanisms and aftershocks hypocenters) recorded during the 1997-98 seismic events. Seismicity seems to be confined above the top of the Basement: this lithological and mechanical discontinuity is suitable to be the base of the seismogenic layer in this region.

Description: Published

Description: 891-900

Description: 3.2. Tettonica attiva

Description: open

Description: Eight cases of large-scale gravitational movements (with evidence of rock-slide type displacements) evolving close to Quaternary faults have been analysed in the Central Apennines. Geomorphological and structural surveys have defined the relationship between the gravitational displacements and the tectonically-controlled modifications of the landscape. The evolution of all the investigated cases has been conditioned by the presence of fault planes located along the mountain slopes. In most cases (Mt. Cefalone, Cima della Fossa, Villavallelonga, Casali d'Aschi, Gioia dei Marsi), the faults played or are playing a primary role in increasing the local relief and their activity represents the main geomorphic factor conditioning the gravitational movements. This kind of relationship has been observed along mountain slopes bordering depressions which have not been drained for most of their geomorphic history or have been characterised by an evolution of the hydrographic network that has been conditioned only by the local tectonic subsidence. In such cases, the gravitational movements develop in the footwalls of the faults. In other cases (Fiamignano, Pescasseroli) the faults have played a passive role, since they only bound the sliding masses and coincide with the surficial expressions of the sliding planes. Therefore, the gravitational displacements develop in the hangingwall of the faults. The evolution is conditioned by the incision of the hydrographic network in response to regional Quaternary uplift. The illustrated case studies provide a wide range of examples of the gravitational response of slopes to the modifications of the landscape due to linear and areal tectonics. The identification of the geomorphic traces of the large-scale gravitational movements along fault-controlled mountain fronts has implications for hazard, particularly for the evolution of the displacement. The quantitative analysis of the vertical displacements and data on the characteristics of the surface breaking during historical earthquakes demonstrate that along-fault offsets strongly increases where the unstable large-scale rock masses are located. Therefore, the large coseismic vertical offset may represent a major problem for the displacement of utilities and may represent a potential cause for the sudden and catastrophic evolution of the gravitational movement.

Description: Published

Description: 201-228

Description: JCR Journal

Description: reserved

Description: INGV. SNAM

Description: Unpublished

Description: reserved

Description: This paper presents the results of different numerical analyses (nonlinear dynamic FEM simulations) regarding the monumental buildings in Ripabottoni village (Campobasso, southern Italy), which were damaged by the 2002 Molise earthquake. In particular, the church of S. Maria Assunta, for which typological data and an exhaustive damage survey are available, is taken into account. Some preliminary studies [Spallarossa et al., 2004], which correlate the waveform of the available recordings from aftershocks and the surveyed damage mechanism (due to the crushing of the vertical structural elements), suggested that a feasible explanation for this particular damage pattern does not involve only the intrinsic vulnerability of this type of buildings, but deals also with the high energy content in the high frequency range observed in the vertical component of the seismic events. In order to understand the structural damage patterns surveyed, synthetic accelerograms, representative of the main shock (Ml = 5.4 on 31 October 2002), were computed. The Empirical Green Function (EGF) method was applied to compute the seismic input adopted in the nonlinear dynamic analyses that we performed for the church of S. Maria Assunta. The results confirm that the observed damage pattern cannot totally be put down to the vulnerability of the building, but the particular characteristics of the seismic action played a fundamental role in determining it.

Description: Published

Description: 381-409

Description: reserved

Description: In this article the implementation and potential of the Seismotectonic Information System of the Campania Region (SISCam) are described, in particular an application of this Web-based GIS system to the seismotectonic analysis of the Sannio area (Southern Apennines) is performed. WEB-GIS technologies greatly contribute to both the environmental monitoring and the disaster management of areas affected by high natural risks. Specifically the SISCam system has been developed with the aim of providing easy access and fast diffusion, through Internet technology, of the most significant geological, geophysical, and territorial data relative to the Campania Region. The Sannio area has been selected as our application example because it is among the most active seismic regions in Italy. This portion of the Southern Apennines which was hit by the June 5, 1688 strong earthquake (MW = 6.7, CPTI 1999) and by some low- and moderate-energy seismic sequences (1990–1992, 1997), is characterized by a complex inherited tectonic setting and low-tectonic deformation rates that hide the seismogenic sources position. Since this case study turned out to be complicated, the use of the SIScam WEB-GIS has become indispensable because it allowed us to visualize, integrate and analyze all the data available, in order to obtain an accurate and direct picture of the seismotectonic setting of the area. Moreover, a different approach of data analysis was necessary, due to the lack of up-todate neotectonic and structural data; therefore, the operation of this GIS system enabled us to process and generate some original informative layers, through image analysis, such as new structural lineaments represented on a map of the potential active faults of the area, which has been the final result of our application, as a contribution to new knowledge about the local seismic risk parameters.

Description: Published

Description: on line first

Description: 5.4. TTC - Sistema Informativo Territoriale

Description: JCR Journal

Description: reserved

Description: Istituto Nazionale di Geofisica e Vulcanologia Dipartimento della Protezione Civile

Description: Unpublished

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: On the night between 14 and 15 January of 1466, an earthquake damaged towns close to those recently destroyed by the 1980 Irpinia earthquake. It was felt in Naples, about 80 km from the epicentre, resulting in panic and slight damage. To obtain source parameters related to January 15, 1466, the observed macroseismic field of the November 23, 1980 earthquake was reproduced by synthetic peak strong acceleration. The results suggest that the whole of the 1466 faulting was also activated by the 1980 event, and that the northern part remained non-activated. Quite possibly, the near southernmost source of a large earthquake in 1456 affected the occurrence of the event nearby ten years later. Furthermore, the value of Mo=7.5 1018 Nm obtained allows the medieval event in 1466 to number among the most severe recorded in southern Italy.

Description: Published

Description: 115-126

Description: 3.1. Fisica dei terremoti

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: 3.10. Sismologia storica e archeosismologia

Description: 5.1. TTC - Banche dati e metodi macrosismici

Description: N/A or not JCR

Description: reserved

Description: We present the state of advancement of a new version of the Database of Potential Sources for Earthquakes larger than M 5.5 in Italy (Valensise e Pantosti, 2001, Annali di Geofisica, Suppl. to vol. 44, 4, 180 pp., with CD-ROM). The main object of the database is the seismogenic source, intended as a simplified and georeferenced 3D representation of a fault plane. The seismogenic source is identified through geological and geophysical investigations and is assumed to be capable of primary slip during a large earthquake. Seismogenic sources for which geological and seismological data are insufficient are derived from quantitative treatment of historical earthquake data. The Database is implemented on a GIS platform and is open to additions and improvements. We devoted the last three years to improve specific information on previously identified seismogenic sources and to implement new ones. The updated Database contains 100 seismogenic sources based on geological/geophysical data (40 more than the previous version). These sources cover the whole Italian territory and some conterminous regions. They also show the fundamental architecture of major active fault systems, thus highlighting areas of limited seismic release and potential seismic gaps. The Database also includes: 1) about 1,700 selected references to scientific literature (1,256 in the previous version) specifically pertinent to the identified seismogenic sources; 2) new pictures selected from the literature, such as geological maps, cross-sections, and photographs; 3) an improvement of the section dedicated to basic georeferenced geological/geophysical data. As a result of these improvements the end users will benefit from a better definition of already outlined seismogenic fault systems and the identification of new ones, along with a more reliable documentation supporting the database content. DISS 3.0 will hopefully stimulate innovative seismic hazard assessment approaches based on the use of individual seismogenic sources.

Description: Published

Description: Potsdam, Germany

Description: 3.2. Tettonica attiva

Description: open

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: open

Description: Published

Description: 3.10. Sismologia storica e archeosismologia

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: 5.8. TTC - Formazione e informazione

Description: open

Description: Seismically induced environmental effects (in particular, surfacefaults, ground cracks, slope failures, liquefaction, soil compaction, hydrological changes, tsunamis) are assumed to provide fundamentalinformation on the earthquake size and its intensity field, crucial for a more efficient seismic hazard assessment. Accordingly, this study is aimed at substantiating this assumption by showing that the knowledge about ground effects acquired in recent earthquakes, when combined with that illustrated in historical documents, allows to buildan improved picture of historic seismic events, with respect to that usually provided by the solely damage-based macroseismic scales. In this perspective, the environmental effects are analysed and cataloguedof three of the most ruinous earthquakes in Southern Italy of the last two centuries: the July 26,1805, Molise event (XI MCS, M 6.8), the July 23, 1930, Irpinia event (X MCS, M 6.7), and the November 23, 1980 Campania-Basilicata event (X MSK, Ms 6.9). The distribution of the earthquake environmental effects, in particular their distance from the known or supposed causative fault, has been investigated to obtain a more detailed and comprehensive picture of the macroseismic field, a key parameter in seismic hazard assessment and seismic zonation. KEY WORDS: historical seismicity, intensity, ground effects, earthquake

Description: Published

Description: 333-346

Description: 3.10. Sismologia storica e archeosismologia

Description: JCR Journal

Description: open

Description: Two layers of fine sand of marine origin occur in a sequence of organic rich colluvia in an archaeological excavation at Torre degli Inglesi, on Capo Peloro, northeast Sicily. Stratigraphic and micropaleontologic analyses support the hypothesis that these layers are related to deposition due to paleotsunami waves. Their ages are constrained both with radiocarbon and archaeological datings. The age of the oldest layer is coincident with the 17 A.D. earthquake that hit Reggio Calabria but for which no tsunami was previously reported. The age of the youngest layer can be only constrained in the range 3rd– 19th century and is tentatively associated to the 6 Feb. 1783 event.

Description: Italian Civil Protection Department in the frame of the 2004 – 2006 agreement with Istituto Nazionale di Geofisica e Vulcanologia – INGV (Seismological Project S2) and E.C. project TRANSFER (contract 037058)

Description: Published

Description: L05311

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: partially_open

Description: In the framework of the 2004 reference seismic hazard map of Italy the amplitude of the strong-motion (expressed in terms of Peak Horizontal Acceleration with 10% probability of non-exceedence in 50 years, referred to average hard ground conditions) was computed using different predictive relationships. Equations derived in Italy and in Europe from strong-motion data, as well as a set of weak and strong-motion based empirical predictive relationships were employed in a logic tree procedure, in order to capture the epistemic uncertainty affecting ground-motion attenuation. This article describes the adjustments and conversions required to eliminate the incompatibilities amongst the relations. Particularly significant are distance conversions and style-of-faulting adjustments, as well as the problems related to the use of regional relations, such as the selection of a reference depth, the quantification of random variability and the strong-motion prediction. Moreover, a regional attenuation relationship specific for volcanic areas was also employed, allowing a more realistic evaluation of seismic hazard, as confirmed by the attenuation of macroseismic intensities.

Description: Published

Description: 295-316

Description: 4.2. TTC - Scenari e mappe di pericolosità sismica

Description: JCR Journal

Description: reserved