ALBERT

Description: Since August 2016, central Italy has been struck by one of the most important seismic sequences ever recorded in the country. In this study, a strong-motion data set, consisting of nearly 10,000 waveforms, has been analyzed to gather insights about the main features of ground motion, in terms of regional variability, shaking intensity, and near-source effects. In particular, the shake maps from the three main events in the sequence have been calculated to evaluate the distribution of shaking at a regional scale, and a residual analysis has been performed, aimed at interpreting the strong-motion parameters as functions of source distance, azimuth, and local site conditions. Particular attention has been dedicated to near-source effects (i.e., hanging wall/footwall, forward-directivity, or fling-step effects). Finally, ground-motion intensities in the near-source area have been discussed with respect to the values used for structural design. In general, the areas of maximum shaking appear to reflect, primarily, rupture complexity on the finite faults. Large ground-motion variability is observed along the Apennine direction (northwest–southeast) that can be attributed to source-directivity effects, especially evident in the case of small-magnitude aftershocks. Amplifications are observed in correspondence to intramountain basins, fluvial valleys, and the loose deposits along the Adriatic coast. Near-source ground motions exhibit hanging-wall effects, forward-directivity pulses, and permanent displacement.

Description: In this paper we present and discuss the performance of the procedure for earthquake location and characterization implemented in the Italian Candidate Tsunami Service Provider at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome. Following the ICG/NEAMTWS guidelines, the first tsunami warning messages are based only on seismic information, i.e., epicenter location, hypocenter depth, and magnitude, which are automatically computed by the software Early-est. Early-est is a package for rapid location and seismic/tsunamigenic characterization of earthquakes. The Early-est software package operates using offline-event or continuous-real-time seismic waveform data to perform trace processing and picking, and, at a regular report interval, phase association, event detection, hypocenter location, and event characterization. Early-est also provides mb, Mwp, and Mwpd magnitude estimations. mb magnitudes are preferred for events with Mwp ≲ 5.8, while Mwpd estimations are valid for events with Mwp ≳ 7.2. In this paper we present the earthquake parameters computed by Early-est between the beginning of March 2012 and the end of December 2014 on a global scale for events with magnitude M ≥ 5.5, and we also present the detection timeline. We compare the earthquake parameters automatically computed by Early-est with the same parameters listed in reference catalogs. Such reference catalogs are manually revised/verified by scientists. The goal of this work is to test the accuracy and reliability of the fully automatic locations provided by Early-est. In our analysis, the epicenter location, hypocenter depth and magnitude parameters do not differ significantly from the values in the reference catalogs. Both mb and Mwp magnitudes show differences to the reference catalogs. We thus derived correction functions in order to minimize the differences and correct biases between our values and the ones from the reference catalogs. Correction of the Mwp distance dependency is particularly relevant, since this magnitude refers to the larger and probably tsunamigenic earthquakes. Mwp values at stations with epicentral distance Δ ≲ 30° are significantly overestimated with respect to the CMT-global solutions, whereas Mwp values at stations with epicentral distance Δ ≳ 90° are slightly underestimated. After applying such distance correction the Mwp provided by Early-est differs from CMT-global catalog values of about δ Mwp ≈ 0.0 ∓ 0.2. Early-est continuously acquires time-series data and updates the earthquake source parameters. Our analysis shows that the epicenter coordinates and the magnitude values converge within less than 10 min (5 min in the Mediterranean region) toward the stable values. Our analysis shows that we can compute Mwp magnitudes that do not display short epicentral distance dependency overestimation, and we can provide robust and reliable earthquake source parameters to compile tsunami warning messages within less than 15 min after the event origin time.

Description: In this paper we present the procedure for earthquake location and characterization implemented in the Italian candidate Tsunami Service Provider at INGV in Roma. Following the ICG/NEAMTWS guidelines, the first tsunami warning messages are based only on seismic information, i.e. epicenter location, hypocenter depth and magnitude, which are automatically computed by the software Early-est. Early-est is a package for rapid location and seismic/tsunamigenic characterization of earthquakes. The Early-est software package operates on offline-event or continuous-realtime seismic waveform data to perform trace processing and picking, and, at a regular report interval, phase association, event detection, hypocenter location, and event characterization. In this paper we present the earthquake parameters computed by Early-est from the beginning of 2012 till the end of December 2014 at global scale for events with magnitude M ≥ 5.5, and the detection timeline. The earthquake parameters computed automatically by Early-est are compared with reference manually revised/verified catalogs. From our analysis the epicenter location and hypocenter depth parameters do not differ significantly from the values in the reference catalogs. The epicenter coordinates generally differ less than 20 ∓ 20 km from the reference epicenter coordinates; focal depths are less well constrained and differ generally less than 0 ∓ 30 km. Early-est also provides mb, Mwp and Mwpd magnitude estimations. mb magnitudes are preferred for events with Mwp ≲ 5.8, while Mwpd are valid for events with Mwp ≳ 7.2. The magnitude mb show wide differences with respect to the reference catalogs, we thus apply a linear correction mbcorr = mb · 0.52 + 2.46, such correction results into δmb ≈ 0.0 ∓ 0.2 uncertainty with respect the reference catalogs. As expected the Mwp show distance dependency. Mwp values at stations with epicentral distance Δ ≲ 30° are significantly overestimated with respect the CMT-global solutions, whereas Mwp values at stations with epicentral distance Δ ≳ 90° are slightly underestimated. We thus apply a 3rd degree polynomial distance correction. After applying the distance correction, the Mwp provided by Early-est differs from CMT-global catalog values of about δ Mwp ≈ 0.0 ∓ 0.2. Early-est continuously acquires time series data and updates the earthquake source parameters. Our analysis shows that the epicenter coordinates and the magnitude values converge rather quickly toward the final values. Generally we can provide robust and reliable earthquake source parameters to compile tsunami warning message within less than about 15 min after event origin time.

Description: Universal Mobile Telecommunications System (UMTS) and its evolutions are nowadays the most affordable and widespread data communication infrastructure available almost world wide. Moreover the always growing cellular phone market is pushing the development of new devices with higher performances and lower power consumption. All these characteristics make UMTS really useful for the implementation of an "easy to deploy" temporary real-time seismic station. Despite these remarkable features, there are many drawbacks that must be properly taken in account to effectively transmit the seismic data: Internet security, signal and service availability, power consumption. – Internet security: exposing seismological data services and seismic stations to the Internet is dangerous, attack prone and can lead to downtimes in the services, so we setup a dedicated Virtual Private Network (VPN) service to protect all the connected devices. – Signal and service availability: while for temporary experiment a carefull planning and an accurate site selection can minimize the problem, this is not always the case with rapid response networks. Moreover, as with any other leased line, the availability of the UMTS service during a seismic crisis is basically unpredictable. Nowadays in Italy during a major national emergency a Committee of the Italian Civil Defense ensures unified management and coordination of emergency activities. Inside it the telecom companies are committed to give support to the crisis management improving the standards in their communication networks. – Power consumption: it is at least of the order of that of the seismic station and, being related to data flow and signal quality is largely unpredictable. While the most secure option consists in adding a second independent solar power supply to the seismic station, this is not always a very convenient solution since it doubles the cost and doubles the equipment on site. We found that an acceptable trade-off is to add an inexpensive Low Voltage Disconnect (LVD) circuit to the UMTS router power supply that switches off the data transmission when the power is low. This greatly reduces the probability of data loss but lowers the real-time data availabilty. This approach guarantees on the average a satisfactory data acquistion rate, only in very few cases and when the real-time data is extremely important for a particular site we needed to double the power supply on the site. Overall the UMTS data transmission has been used in most temporary seismic experiments and in all seismic emergencies happened in Italy since 2010 and has proved to be a very cost effective approach with real-time data acquisition rates usually greater than 97 % and all the benefits that result from the fast integration of the temporary data in the National Network monitoring system and in the EIDA data bank.

Description: Alle ore 02.03 UTC di domenica 20 maggio 2012, la Rete Sismica Nazionale (RSN [Amato and Mele, 2008; Delladio, 2011]) dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) ha registrato un evento simico di magnitudo locale 5.9 che è stato avvertito in gran parte dell’Italia centro-settentrionale; l’evento è stato localizzato sotto la valle del Po in Emilia (44.89° N, 11.23° E e 6.3 km di profondità). Subito dopo la scossa principale, è stato attivato il Pronto Intervento Sismico dell’INGV al fine di installare una rete sismica temporanea ad integrazione delle stazioni permanenti già presenti in area epicentrale. Grazie alla collaborazione fra le sedi INGV di Ancona, Arezzo, Bologna, Irpinia (Grottaminarda), Milano, Pisa e Roma sono state installate 44 stazioni temporanee, di cui 10 in trasmissione real-time con la sala di sorveglianza simica della sede di Roma. Contemporaneamente altre 38 stazioni sismiche temporanee sono state inoltre installate dal Dipartimento della Protezione Civile – DPC (16 stazioni strong motion), dall’Istituto Nazionale di Oceanografia e di Geofisica Sperimentale – OGS (8 stazioni stand-alone) e da enti francesi (14 stazioni stand-alone). In una seconda fase, l’8 giugno 2012, è stato attivato anche il Centro Operativo Emergenza Sismica (COES [Moretti et al., 2010a]), all’interno della Direzione di Comando e Controllo (Di.Coma.C.) del DPC predisposto presso l’Agenzia della Protezione Civile Regionale dell’Emilia Romagna (Bologna). L’allestimento e il coordinamento della struttura sono stati realizzati grazie alla collaborazione tra il Centro Nazionale Terremoti (CNT) e la Sezione di Bologna. Il COES ha garantito la comunicazione costante e diretta con i funzionari DPC presenti nell'area epicentrale. Allo stesso tempo, la struttura è stata proposta come supporto logistico per tutti i colleghi dell’INGV impegnati in attività nella zona epicentrale (reti sismiche Mobili, EMERSITO, GPS, EMERGEO, QUEST) e per sostenere il servizio dedicato alla “Comunicazione e Informazione” promosso a favore delle popolazioni colpite, degli operatori della protezione civile e dei volontari di soccorso. In questo lavoro saranno descritte le attività svolte nel primo mese di emergenza, le modalità e le tempistiche dell’intervento, le strutture coinvolte.

Description: Published

Description: 1-43

Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale

Description: N/A or not JCR

Description: open

Description: Il 6 aprile 2009 (3.32 locali) un terremoto di Mw 6,3 ha colpito la regione Abruzzo (Italia centrale) producendo un enorme danno alla città de L'Aquila e ai paesi limitrofi causando circa 300 morti e 60.000 senza fissa dimora. A seguito di questo evento sismico, la struttura di Pronto Intervento dell’INGV (Istituto Nazionale di Geofisica e Vulcanologia), si è rapidamente attivata installando in area epicentrale due reti sismiche temporanee (Re.Mo.Tel. in real-time e Re.Mo. in stand-alone) ed il Centro Operativo Emergenza Sismica. In questo lavoro presentiamo come si e’ svolta la campagna sismica della Re.Mo., avente l’obiettivo di acquisire dati di alta qualità e dettaglio per studiare le sorgenti sismiche, l’evoluzione spazio temporale della sequenza e caratterizzare attraverso la microsismicita’ le strutture di faglia attivate ed le proprieta’ del mezzo circostante. Saranno descritte nel dettaglio l’installazione compiuta a poche ore dal mainshock, il suo sviluppo legato all’evoluzione della sequenza sismica, fino alla sua dismissione nel Marzo 2010.

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale

Description: open