ALBERT

Description: EU project ASTARTE aims at developing a higher level of tsunami hazard assessment in the North East Atlantic and Mediterranean (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the description of past tsunamigenic events, the characterization of tsunami sources, the calculation of the impact of such events, and the development of adequate resilience strategies (www.astarte.eu). Within ASTARTE a web-based data base on Paleotsunami Deposits in the NEAM areas is being created that will be the future reference source for this kind of research in Europe. The aim is to integrate every existing scientific reference on the topic and update on new entries every six months, hosting information and detailed data that are crucial, e.g for tsunami modeling. At present 127 sites with evidence for at least one paleotsunami deposit have been collected. A relational database managed by ArcGIS for Desktop 10.3 software has been implemented to allow all partners to collaborate through a common platform for archiving and exchanging data and interpretations, such as paleotsunami type of evidence (sediment, blocks, geomorphological signature, etc), geometric characteristics (thickness, depth, etc), but also age and dating method and type of analysis supporting the tsunami interpretation. Moreover, information on the type of the site (natural or artificial exposure, exploratory trench, hand or engine core, etc), on its geomorphic setting (coastal lake, marsh, fluvial plain, offshore, etc) and on its elevation and distance from the present shoreline are provided. One of the final goals of the project is the public sharing of the archived datasets through a web-based map service that will allow to visualize, question, analyze, and interpret all datasets. The interactive map service will be hosted by ArcGIS Online and will deploy the cloud capabilities of the portal. Any interested users will be able to access the online GIS resources through any Internet browser or specific apps that run on desktop machines, smartphones, or tablets and will be able to use the analytical tools, key tasks, and workflows of the service. The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe).

Description: Published

Description: Wien, Austria

Description: 5T. Modelli di pericolosità sismica e da maremoto

Description: EU project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe, Project # 603839) aims at reaching a higher level of tsunami resilience in the North East Atlantic and Mediterranean (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the description of past tsunamigenic events, the characterization of future tsunami sources, the calculation of the impact of such events, and the development of adequate resilience strategies (www.astarte.eu).

Description: Published

Description: San Francisco, USA

Description: 5T. Modelli di pericolosità sismica e da maremoto

Description: he study of coseismic surface ruptures provides insights into earthquakes dynamics and fault growth processes. We analyze the surface faulting related to the seismic sequence that hit central Italy in 2016–2017, focusing on the ruptures caused by 30 October 2016 Mw 6.5 Norcia earthquake. They are located on the NW trending normal fault splays of the Mount Vettore-Mount Bove fault system (VBFS), forming a fracture network made of hundreds of strands striking N135–160°. The surface rupture length for this event is ~22 km, with average surface slip of ~0.44 m and peak of ~2.10 m. The collected coseismic slip vectors yield an average N233° trending extension, consistent with the local structural setting and seismological data. Surface slip displays cumulative frequency-size distributions of rupture length and offset that follow power law and exponential scaling over 2 orders of magnitude, respectively. We observe strain localization on a few major fault splays of the VBFS, causing a markedly asymmetric along-strike slip profile, with a high gradient to the southeast. The ~5-km-long Cordone del Vettore fault accounts for 40% of the overall coseismic surface slip. We infer that the heterogeneous slip at depth, coupled with the highly segmented nature of the VBFS and its interference with thrusts and adjacent active normal faults, has control over the pattern of surface faulting. For the Norcia earthquake, a robust scaling of surface slip area with rupture length accounts for extreme slip peaks over relatively short ruptures, which we envisage may be typical of the VBFS long- term growth.

Description: Published

Description: 3378-3410

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: We conducted paleoseismic studies along the Montereale fault system (MFS; central Italy). The MFS shows geomorphological evidence of Late Quaternary activity and falls within the highest seismic hazard zone of central Apennines, between the epicentral areas of two recent earthquake sequences: 2009 L’Aquila and 2016–2017 central Italy. We excavated two trenches along the San Giovanni fault splay of the system, one intercepting the N140° striking bedrock main fault plane and the other cutting two subparallel fault scarps on the colluvial/alluvial deposits on the fault hanging wall. Excavations revealed repeated fault reactivation with surface faulting in prehistorical and historical times. We recognized and dated seven events in the last 26 kyr. The most recent ground-rupturing event (evb1) possibly occurred 650–1,820 AD, consistent with one of the three main shocks that struck the area in 1,703 AD. A previous event (evb2) occurred between 5,330 BC and 730 BC, while older events occurred at 6,590–5,440 BC (evb3), 9,770–6,630 BC (evb4), and 16,860–13,480 BC (evb5). We documented two older displacement events (evb7 and evb6) between 23,780 BC and 16,850 BC. The minimum vertical slip rate at the trench site in the last 28–24 kyr is 0.3–0.4 mm/year. The inferred average recurrence interval for surface-faulting events along the MFS is no longer than ~4 kyr. Based on the surface fault length ranging between 12 and 20 km, earthquakes with ≥M 6.0 are possible for the MFS. The MFS is an independent earthquake source, and its paleoseismic data are fully comparable with those known for faults in central Apennines.

Description: Published

Description: 2758-2776

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: We integrate paleoseismic data sets along the Mt. Vettore‐Mt. Bove normal fault system rupturing at the surface in the 30 October 2016 Norcia earthquake. Through the analysis of new trenches from this work and a review of the preexisting data, we correlate events among trench sites along antithetic and synthetic fault splays. We recognize seven M 6.5, 2016 Norcia‐type (or larger) surface‐faulting events in the last ~22 kyr, including 2016. Before 2016, one event occurred in the past two millennia (260–575 CE) and possibly corresponds to the event damaging Rome in 443 or 484/508 CE. Three previous events occurred between 10590 and 415 BCE, whereas the two oldest ones date between 19820 and 16540 BCE. The average recurrence time is 3,360–3,640 years for the last ~22 kyr and 1,220–1,970 years for the last ~4 kyr. We infer a minimum dip‐slip rate of 0.26–0.38 mm/year on the master fault in the central portion of the Mt. Vettore–Mt. Bove normal fault system and a dip‐slip rate of at least 0.10 mm/year on the southernmost portion. We infer a Middle–Late Pleistocene inception of the long‐term scarp of the investigated splays. The along‐strike variation of slip rates well reproduces the trend of the 2016 surface slip; thus, the time window exposed in the trenches is representative for the present fault activity. Based on trenching data, different earthquake rupture scenarios should be also considered for local hazard assessment.

Description: Published

Description: 9021-9048

Description: 4T. Sismicità dell'Italia

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: 7A. Geofisica per il monitoraggio ambientale

Description: 4IT. Banche dati

Description: JCR Journal

Description: This article is a response to the publication by Nick Marriner, David Kaniewski, Christophe Morhange, Clément Flaux, Matthieu Giaime, Matteo Vacchi and James Goff entitled “Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean”, published in October 2017 in Science Advances. Making use of radiometric data sets published in the context of selected palaeotsunami studies by independent research groups from different countries, Marriner et al. (2017) carried out statistical and time series analyses. They compared their results with an assessment of Mediterranean storminess since the mid-Holocene that was previously published by Kaniewski et al. (2016) based on a single-core study from coastal Croatia. Marriner et al. (2017) now present “previously unrecognized” 1500-year “tsunami megacycles” which they suggest correlating with Mediterranean climate deterioration. They conclude that up to 90 % of all the ‘tsunamis’ identified in original tsunami papers used for their study are “better as­ cribed to periods of heightened storminess”. In this response, we show that (i) the comparison of statistical data describing storm and tsunami events presented by Marriner et al. (2017) is incorrect both from a geographical and a statistical point of view, (ii) the assumed periods of central Mediterranean storminess published by Kaniewski et al. (2016) are missing convincing geological and geochronological evidence and are statistically incorrect, (iii) the palaeotsunami data that was originally collected by different groups of authors were manipulated by Marriner et al. (2017) in a way that the resulting data set – used as a benchmark for the entire study of these authors – is wrong and inaccurate, and that (iv) Marriner et al. (2017) did not address or even negate the original sedimentological studies’ presentation of comparative tsunami versus storm deposits for the selected individual localities. Based on a thorough and detailed evaluation of the geoscientific background and the methodological approach of the studies by Kaniewski et al. (2016) and Marriner et al. (2017), we conclude that there is no serious and reliable geoscientific evidence for increased storminess in the (central) Mediterranean Sea between 3400–2550, 2000–1800, 1650–1450, 1300–900 and 400–100 cal BP. The impact of those storms in the Mediterranean, producing geological traces somewhat comparable to those caused by tsunamis, is insignificantly small. For the period 1902–2017, Mediterranean tsunamis make up 73–98 % of all com- bined extreme wave events (EWE) leading to coastal flooding and appeared up to 181 times deadlier than comparable storm effects. This is the reason why coastal Mediterranean research has focused on Holocene records of the tsunami hazard, while research on comparable storm effects is of lower significance. The validity of geological evidence for Mediterranean EWE and their interpretation as caused by palaeotsunami impacts thus remains untouched. Tsunamis, in most cases directly and indirectly induced by seismo-tectonics, have always been a much greater threat to Mediterranean coastal regions than com- parable storm effects. ‘Tsunami megacycles’ as expressions of a 1500-year periodicity centered on the Little Ice Age, 1600 and 3100 cal BP that were correlated with questionable storm data do not exist. Cause and effect relationships work the other way round: Major tsunami events, testified by historical accounts, such as those that occurred in 1908 AD, 1755 AD, 1693 AD and 365 AD, induced numerous studies along Mediterranean coasts. These investigations resulted in a large number of publications that specifically focus on those time periods, suspected by Marriner et al. (2017) to bear signs of increased storminess, namely 200–300 BP and 1600 BP. The Mediterranean tsunami record cannot be ascribed to periods of increased storminess. On the contrary, the tsunami record as interpreted by the authors of the original papers cited by Marriner et al. (2017), is due to the outstandingly high seismo-tectonic activity of the region. Mediterranean tsunamis are mostly triggered by earthquakes or by earthquake-related secondary effects such as underwater mass movements. The study by Marriner et al. (2017) is also problematic because it includes simple basic statisti- cal mistakes and major methodological inconsistencies. The geomorphological and sedimentary back- ground of EWE deposits was not taken into account. The ‘broad brush’ approach used by Marriner et al. (2017) to sweep sedimentary deposits from tsunami origin into the storm bag origin, just on the basis of (false) statistics coupled with very broad and unreliable palaeoclimatic indicators and time frames, is misleading. The distortion of original data collected and interpreted by other research groups by Marriner et al. (2017) is particularly disturbing. Their publication is also bound to question in this case the effective- ness of scientific quality assurance in modern publishing commerce. Marriner et al. (2017: 7) talk down the considerable risk to human settlements and infrastructure along Mediterranean coasts in relation to tsunami and earthquake hazards. Their conclusion is not only wrong as a result of their incorrect data mining and analyses, it is also irresponsible with regard to national and international efforts of tsunami and earthquake risk mitigation.

Description: Published

Description: 7-45

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal