Emergenza sismica nel centro Italia 2016-2017. Secondo rapporto del gruppo operativo SISMIKO. Sviluppo e mantenimento della rete sismica mobile a seguito del terremoto di Amatrice Mw 6.0 (24 agosto 2016, Italia centrale)

La rete sismica temporanea installata dal gruppo operativo INGV SISMIKO a seguito del terremoto del 24 agosto 2016 tra i Monti della Laga e la Valnerina, è stata ampliata nel settore settentrionale a seguito dei forti terremoti avvenuti alla fine del mese di ottobre 2016. Successivamente alle due scosse di Mw 5.4 e 5.9 che il 26 ottobre hanno interessato l’area al confine Marche-Umbria tra i Comuni di Castelsantangelo sul Nera (MC), Norcia (PG) e Arquata del Tronto (AP), la geometria della rete è stata estesa di circa 25 km verso nord con l’attivazione di ulteriori tre stazioni temporanee di cui una, da subito, disposta per la trasmissione dei dati in tempo reale e per l’inserimento nel sistema di sorveglianza sismica dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV). Un’ultima stazione è stata inoltre installata nei pressi di Campello del Clitunno in provincia di Perugia ad ovest della sequenza, a seguito del terremoto Mw 6.5 che la mattina del 30 ottobre ha interessato l’intera area già fortemente provata dalla sequenza in corso; questo è stato il più forte terremoto registrato negli ultimi 30 in Italia. A circa 5 mesi dall’inizio dell’emergenza sismica, la rete temporanea conta quindi 23 stazioni che da metà dicembre sono tutte trasmesse in tempo reale ai diversi centri di acquisizione INGV, ovvero Milano, Ancona e Grottaminarda ma soprattutto Roma dove i dati vengono contestualmente archiviati nell’European Integrated Data Archive (EIDA) e integrati nel sistema di monitoraggio e sorveglianza sismica dell’INGV; per la sorveglianza sono incluse solo parte delle stazioni. Nelle ultime settimane, le attività di campagna del gruppo operativo SISMIKO sono state costantemente focalizzate alla cura e alla manutenzione della strumentazione per garantire la continuità della trasmissione e dell’acquisizione dei dati, a volte compromesse da malfunzionamenti legati al maltempo. Alla data di aggiornamento del presente report, non è ancora stata decretata una dismissione o una rimodulazione della geometria della rete sismica temporanea, anche in considerazione della attività sismica in corso a tutt’oggi molto sostenuta. Tutti i dati acquisiti dalle stazioni temporanee SISMIKO, sono distribuiti senza alcun vincolo, al pari dei dati della Rete Sismica Nazionale (RSN, codice di rete IV), ed utilizzati per prodotti scientifici in tempo reale (localizzazioni di sala, calcolo dei Time Domain Moment Tensor -TDMT delle ShakeMaps, ecc) e per l’aggiornamento dei database dell’INGV come l’Italian Seismological Instrumental and Parametric Database (ISIDe) con la revisione del Bollettino Sismico Italiano (BSI), dell’INGV Strong Motion Data (ISMD) e dell’ITalian ACcelerometric Archive (ITACA), dell’European-Mediterranean Regional Centroid Moment Tensors (RCMT) e nei lavori scientifici che utilizzano forme d’onda velocimetriche ed accelerometriche (ri- localizzazioni, studi della sorgente sismica ecc.).Istituto Nazionale di Geofisica e Vulcanologia (INGV)Published1SR. TERREMOTI - Servizi e ricerca per la Societ

Rapporto Preliminare Sulle Attività Svolte Nel Primo Mese Di Emergenza Dal Gruppo Operativo Sismiko A Seguito Del Terremoto Di Amatrice Mw 6.0 (24 Agosto 2016, Italia Centrale)

Sintesi delle attività svolte dal coordinamento delle reti sismiche mobili INGV in emergenza, denominato SISMIKO, nel primo mese della sequenza sismica “Amatrice” seguita al terremoto di Mw 6.0 del 24 agosto 2016 (01:36 UTC). Descrizione della rete sismica implementata e prime analisi dei dati acquisiti. Report on the activities in the first month of emergency by coordination of mobile seismic networks INGV emergency, called SISMIKO, after the Mw 6.0 Amatrice earthquake (August 24th, 2016, central italy). Description of the temporary seismic network implemented and preliminary analysis of the acquired data.INGV DPCPublished1IT. Reti di monitoraggi

SISMIKO:emergency network deployment and data sharing for the 2016 central Italy seismic sequence

At 01:36 UTC (03:36 local time) on August 24th 2016, an earthquake Mw 6.0 struck an extensive sector of the central Apennines (coordinates: latitude 42.70° N, longitude 13.23° E, 8.0 km depth). The earthquake caused about 300 casualties and severe damage to the historical buildings and economic activity in an area located near the borders of the Umbria, Lazio, Abruzzo and Marche regions. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) located in few minutes the hypocenter near Accumoli, a small town in the province of Rieti. In the hours after the quake, dozens of events were recorded by the National Seismic Network (Rete Sismica Nazionale, RSN) of the INGV, many of which had a ML > 3.0. The density and coverage of the RSN in the epicentral area meant the epicenter and magnitude of the main event and subsequent shocks that followed it in the early hours of the seismic sequence were well constrained. However, in order to better constrain the localizations of the aftershock hypocenters, especially the depths, a denser seismic monitoring network was needed. Just after the mainshock, SISMIKO, the coordinating body of the emergency seismic network at INGV, was activated in order to install a temporary seismic network integrated with the existing permanent network in the epicentral area. From August the 24th to the 30th, SISMIKO deployed eighteen seismic stations, generally six components (equipped with both velocimeter and accelerometer), with thirteen of the seismic station transmitting in real-time to the INGV seismic monitoring room in Rome. The design and geometry of the temporary network was decided in consolation with other groups who were deploying seismic stations in the region, namely EMERSITO (a group studying site-effects), and the emergency Italian strong motion network (RAN) managed by the National Civil Protection Department (DPC). Further 25 BB temporary seismic stations were deployed by colleagues of the British Geological Survey (BGS) and the School of Geosciences, University of Edinburgh in collaboration with INGV. All data acquired from SISMIKO stations, are quickly available at the European Integrated Data Archive (EIDA). The data acquired by the SISMIKO stations were included in the preliminary analysis that was performed by the Bollettino Sismico Italiano (BSI), the Centro Nazionale Terremoti (CNT) staff working in Ancona, and the INGV-MI, described below

Le attività del gruppo operativo INGV "SISMIKO" durante la sequenza sismica "Amatrice 2016",

SISMIKO è un gruppo operativo dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) che coordina tutte le Reti Sismiche Mobili INGVPublishedLecce3T. Sorgente sismica4T. Sismicità dell'Italia8T. Sismologia in tempo reale1SR TERREMOTI - Sorveglianza Sismica e Allerta Tsunami2SR TERREMOTI - Gestione delle emergenze sismiche e da maremoto3SR TERREMOTI - Attività dei Centr

A mixed automatic-manual seismic catalog for Central-Eastern Italy: analysis of homogeneity

A comparison between pickings and locations obtained by automatic and manual procedures in the analysis of the seismicity of Central-Eastern Italy is presented. In a first step we compared automatic and manual pickings, demonstrating that in many cases the adopted algorithm, after some tuning, is able to reproduce both the timing and the weight assignment of a human operator. The comparison of automatic and manual locations allowed to demonstrate that, when the automatic procedure is able to reach a solution stable from the statistical point of view, these locations are comparable with the manual ones within the estimated error limits. Once established these reliability criteria, we began to produce a mixed automatic-manual catalog: the events located by the automatic procedure with estimated errors below the selected thresholds (2 km in horizontal and 3 km in vertical) were directly introduced in the catalog, other events were revised by a human operator. In this way more than 64% of the events did not need human intervention, allowing to correctly manage also a period of increased seismicity, characterized by more than 4000 events per month: in total 121894 events were located with good accuracy in a time period of less than 7 years (August 2009 – April 2016). In a last step, a further control of the reliability of the whole procedure was performed, by manually analyzing all the events occurred in the last month of the analyzed period and  classified as reliable by the automatic procedure: two expert seismologists interpreted these events, and the comparison demonstrated that the differences between the automatic and manual pickings and locations are slightly larger, but comparable with the differences between two human operators. As  further checks, an analysis of the distribution of the depth estimates on the whole catalog demonstrated that data from the manual or the automatic part are nearly indistinguishable for the central, better monitored area; furthermore the automatic system demonstrated to be able to correctly locate also quarry blasts, with a reasonable estimate of the depth of these very critical events. Finally, a quick  look at the geographical and depth distribution of the seismicity summarized in the catalog is presented; also in this case the main result is the good overlap of automatic and manual locations, at least for the well-monitored areas

Recent seismicity before the 24 August 2016 MW 6.0 Amatrice (Central Italy) Earthquake as recorded by the RESIICO seismic network

We present the seismicity of the last four years before the MW 6.0 earthquake of August 24, 2016, 01:36 UTC in central Italy, with the aim of understanding the preparatory phase of the event. Our preliminary results show that no significant seismic sequence occurred in the months before the mainshock of August 24, 2016 and that there is little similarity between seismicity clusters in the last four years and the aftershocks. We pay attention to differences between the preparatory phase of the Amatrice earthquake and two other seismic sequences: the 2009 L’Aquila earthquake that was preceded by a seismic sequence, and the 2013-2015 Gubbio seismic swarm that, to date, did end without including any strong event.Published4T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa

Strong-motion observations recorded in strategic public buildings during the 24 August 2016 Mw 6.0 Amatrice (central Italy) earthquake

The Marche Region, in collaboration with INGV, has promoted a project to monitoring public strategic buildings with permanent accelerometer installed at the base of the structures. Public structures play a primary role to maintain the functionality of a local community. Information about vibratory characteristics of the building and subsoil, in addition to the seismic instrumental history that describe the seismic shaking at the base of the structure are collected for each buildings. The real-time acquisition of seismic data allows to obtain accelerometric time history soon after the occurrence of an earthquake. The event of 24 August 2016 in Central Italy was an opportunity to test the functionality of this implemented system. In this work the parameters obtained from strong motion data recorded at the base of the structures were analyzed and the values obtained were inserted with some empirical relationships used to provide intensity microseismic values and damage indices

Attività sperimentali per l’implementazione del monitoraggio sismico di edifici pubblici nella Regione Marche

This paper describes a pilot project for the seismic monitoring of public buildings proposed by the Functional Centre of the Security Integrated Policies and Civil Protection Department - Marche Region (DPISPC) and the Ancona branch of National Institute of Geophysics and Volcanology (INGV). The aim of the pilot project is to associate to vulnerability profile more information about vibrational characteristics of the building and subsoil, in addition to the seismic instrumental history that describe the seismic shaking at the base of the structure. To start the pilot project with the available resources, 11 sites in the Regione Marche were identified where there are already permanent accelerometers at the base of public buildings and temporary measurements of ambient seismic noise were carried out, both inside and outside the structures. Frequencies and directions of the main spectral peaks of vibration of buildings were estimated, using spectral analysis techniques. The directional analysis was useful for interpreting the irregular morphology of some spectral peaks resulting from the standard analysis obtained with the composition of the horizontal components of motion. The collected information, combined with the geological and morphological classification of the sites, provide knowledge about seismic response of structures. Moreover, this approach will be compared to other case studies in which the seismic monitoring of individual structures is carried out with large instrumental and computational resources that allow precise and detailed results but difficult to largely apply on the territory.Published1SR. TERREMOTI - Servizi e ricerca per la SocietàN/A or not JC

A catalogue of non-tectonic earthquakes in central-eastern Italy

Quarry explosions and other non-tectonic signals can contaminate seismic catalogues, especially in areas where dense seismic networks allow to detect even low energy events. This paper presents the algorithm adopted for the discrimination of non-tectonic earthquakes in central-eastern Italy, an area with a high rate of events of this kind (4500 were recorded in the 1996-2012 period). Starting from an empirical classification based on the analysis of areas in which the ratio between daytime and nighttime events is strongly anomalous, a waveform similarity approach allows to simplify the procedure of detection making the final classification more robust. The resulting catalogue of non-tectonic earthquakes (quarry blasts and other anomalous signals) is a useful tool for anyone wanting to carry out a careful analysis of the tectonic seismicity of central-eastern Italy.PublishedS03284T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa

Automated control procedures and first results from the temporary seismic monitoring of the 2012 Emilia sequence

After moderate to strong earthquakes in Italy or in the surrounding areas, the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute for Geophysics and Volcanology) activates a temporary seismic network infrastructure. This is devoted to integration with the Italian National Seismic Network (RSN) [Delladio 2011] in the epicentral area, thus improving the localization of the aftershocks distribution after a mainshock. This infrastructure is composed of a stand-alone, locally recording part (Re.Mo.) [Moretti et al. 2010] and a real-time telemetered part (Re.Mo.Tel.) [Abruzzese et al. 2011a, 2011b] that can stream data to the acquisition centers in Rome and Grottaminarda. After the May 20, 2012, Ml 5.9 earthquake in the Emilia region (northern Italy), the temporary network was deployed in the epicentral area; in particular, 10 telemetered and 12 stand-alone stations were installed [Moretti et al. 2012, this volume]. Using the dedicated connection between the acquisition center in Rome and the Ancona acquisition sub-center [Cattaneo et al. 2011], the signals of the real-time telemetered stations were acquired also in this sub-center. These were used for preliminary quality control, by adopting the standard procedures in use here (see next paragraph, and Monachesi et al. [2011]). The main purpose of the present study is a first report on this quality check, which should be taken into account for the correct use of these data. […