ALBERT

Description: The Val d’Agri (VA) oilfield in the Lucanian Apennines (southern Italy), represents the largest onshore in Europe. Since the 1990's, hydrocarbons are produced from a fractured carbonate reservoir with an average extraction rate of 7*104 barrels/day of oil and 3*106 Smc/day of gas. Part of the wastewater has been re-injected since 2006 into a marginal portion of the reservoir by a high-rate well (Costa Molina 2, CM2). Charged by the Italian oil and gas safety authority, the National Institute of Geophysics and Volcanology (INGV) monitors the VA industrial hydrocarbon operations through the research activity of a dedicated working group (CMS, Centro di Monitoraggio del Sottosuolo) and according to the governmental monitoring guidelines. The CMS operates the real-time acquisition and offline analyses of seismic data recorded at 56 seismic stations associated with public and private local seismic networks. The principal aim of the CMS is to investigate the risk associated with industrial activities that can induce or trigger seismic events by producing stress changes within the upper crustal volume. Previous works have highlighted a spatio-temporal relationship between micro-seismicity (ML ≤ 2.2) and wastewater injection, delineating a NE-dipping back-thrust near the CM2. Part of the microseismicity recorded in the southwestern portion of the VA has also been associated with the water level changes of the Pertusillo lake. One of the main challenges is to define an accurate structural setting of the VA to understand the potential of earthquakes in the area and investigate the presence of active faults. The VA consists of a Quaternary extensional tectonic basin and it is one of the areas of highest seismic hazard in Italy (Basilicata, 1857, M7 earthquake). The basin is bounded by two parallel and oppositely dipping normal fault systems: the Monti della Maddalena Fault System (MMFS) on its western side and the Eastern Agri Fault System (EAFS) on the eastern one. The characterization of the ongoing tectonic activity of the MMFS and EAFS, and their hierarchical relationship is still generating debate among the scientific community. We adopt a multidisciplinary approach based on detailed geological-structural, geophysical and seismic analyses, and electrical resistivity tomography, aimed at reconstructing the subsurface geology of the area and recognizing and characterizing the active and capable faults, and the associated potential for local seismic hazard. We present and discuss the results of this work, focusing on the relative location of seismic events that occurred between March and June 2022. The outcomes allow inferring interesting geologic constraints, highlighting the relationships between the distribution of local seismicity and the structural setting of the area in the uppermost crust (depth 〈 6 km).

Description: Published

Description: Vienna

Description: 1T. Struttura della Terra

Description: The phenomenon `earthquake swarm' is well known from numerous locations on Earth but its mechanism and trigger process are still an enigma. The influence of fluids on fluid-driven seismicity is generally well accepted but the temporal behaviour and the migration of activated phases is still an open question. We attempt to answer these open questions by combining the results of research on induced-seismicity with new reliable analyses of full moment tensors (FMTs) of the swarm earthquakes of 2008 to 2018 in Northwest-Bohemia, Czech Republic by Vavryˇcuk et al. (2017, 2021). The FMTs reveal evidence of compressive fracturing as the prevailing focal mechanism during the swarms. Our proposed hypotheses considered these earthquakes as the origin of subsequent pore pressure pulses in the respective active swarm phase. The diffusion of these pore pressure pulses, which could trigger the nearby earthquakes as well as the successive swarm phase in the vicinity after a respective diffusion process in space and time, are the target of this studies. Missing information regarding the real diffusion distances are compiled by a strict statistical approach of a one-to-one analysis of the swarm earthquakes. The analyses suggest that parts of the swarm earthquakes could be triggered by pore pressure diffusion with an estimated diffusivity range of approximately D = 0.01 to 3.0 m2/s. In exceptional cases, which make about 5% of all cases, we have to consider also diffusivities up to 15 m2/s. Examples of hydraulic diffusivities observed in our region of interest confirm this range. Such a process can also be assumed during further swarms in the years 2011 to 2018 because of the continuous and predominant occurrence of compressive fracturing as a focal mechanism beside pure shear and tensile fracturing. Our results could explain for the firsttime the missing link regarding the temporal and spatial migration of the subsequent swarm phases in ourstudied region at Nový Kostel (Northwest-Bohemia, Czech Republic).

Description: Published

Description: 106941

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: Nel sottosuolo della Val D’Agri (Basilicata) è collocato il più grande giacimento di idrocarburi continentale (a terra) Europeo, che viene sfruttato a partire degli anni 90 da un concessionario multinazionale. Su proposta del MISE la Val D’Agri è stata inserita tra i siti pilota per la sperimentazione degli Indirizzi e Linee Guida per il monitoraggio della sismicità, delle deformazioni del suolo e delle pressioni di poro per le aree interessate delle attività antropiche. Per monitorare un’eventuale influenza delle attività produttive sull’attività sismica locale o la deformazione del sottosuolo, dal 2017 l’INGV è stato incaricato dal MiTE (ex MiSE) di mettere in atto un sistema congiunto di monitoraggio geofisico, che oggi può essere considerato il più avanzato d’Italia per il settore.

Description: Published

Description: 109 - 118

Description: 4T. Sismicità dell'Italia

Description: N/A or not JCR

Description: In data 27 Ottobre 2017 si è verificato un evento sismico di Mw 4 con epicentro a Montesano sulla Marcellana (Basilicata), ad una distanza di meno di 10 km dal bordo esterno della concessione idrocarburi Val d'Agri (VA). Trattandosi di un terremoto localizzato al di fuori del Dominio Esteso di monitoraggio (Indirizzi e Linee Guida del MiSE), la rilevanza di tale evento e possibili nessi con le attività di produzione di Oil&Gas non erano stati approfonditi. Considerando che nel passato la Val d'Agri e il Vallo del Diano sono stati colpiti da eventi con magnitudo superiore a M〉6.5, è utile studiare terremoti moderati nell'area in oggetto, ai fini di contribuire a migliorare la caratterizzazione della pericolosità sismica, potenzialmente distruttiva. Approfittando della presenza di un elevato numero di stazioni sismiche operative nell'area della VA e dintorni, analizziamo i parametri sorgente del l'evento principale Mw 4, applicando tecniche sismologiche avanzate per stimare le incertezze associate all'inversione del momento tensore (MT) e per identificare plausibili effetti di direttività. Il MT è dominato da un meccanismo di faglia normale, orientato in direzione NW-SE, con una profondità ipocentrale del centroide di 14 km. L'unico aftershock registrato (ML 2.1) è stato usato come funzione di Green empirica, ai fini di calcolare la funzione temporale apparente della sorgente (ASTF - apparent source time function) dell'evento principale. Durate apparenti in un range tra 0.11 -- 0.21 s (derivate da onde-S) definiscono un pattern azimutale, che indica una rottura asimmetrica bilaterale, con 70% della propagazione in direzione N310$\,^{\circ}$W, suggerendo un piano di rottura immergendo verso sudovest. I nostri risultati evidenziano che il terremoto di Mw 4 a Montesano sulla Marcellano ha attivato un segmento di faglia più profondo, vicino al basamento, eventualmente associato con l'Eastern Agri Fault System. Il basso potenziale di trigger (meno del 10%) provocato dallo stress associato all'esaurimento del giacimento, rende improbabile la possibilità di un evento indotto o innescato per via dell'estrazione trentennale di idrocarburi dal reservoir VA e suggerisce piuttosto un'origine naturale provocato da stress tettonico locale.

Description: Published

Description: virtual

Description: 4T. Sismicità dell'Italia

Description: On January 2017, a snow avalanche devastated a Resort-hotel in the municipality of Rigopiano in Abruzzo (Central Italy), unfortunately killing 29 people. Due to the bad weather conditions, no visual observation was made; many are the questions and hypotheses around this tragic event. On-site inspections revealed that the hotel was horizontally cut by shear forces and dislocated by 48 m in 70°N direction, once the increasing avalanche pressure exceeded the structural shear strength of the building. Analyses of phone calls and inspections of the victims’ mobile phones revealed that the avalanche struck sometime between 15:40 and 15:54 (UTC). Within this eligible 24 min time window, we scanned regional seismograms for any “suspicious” signal that could have been generated by the avalanche and found three weak seismic transients, starting at 15:42:38 UTC, recorded by the nearest operating station GIGS located in the Gran Sasso underground laboratory at a distance of approximately 17 km from Rigopiano. Directional analysis of the strongest seismic avalanche signal, as well as of the synthetic seismograms, match best when assuming a single force seismic source, attacking in direction of 120°N. Hundreds of simulations of the avalanche dynamics – calculated by using a 2D rapid mass movement simulator – indicate that the seismic signals were rather generated as the avalanche flowed through a narrow and twisting canyon directly above the hotel. Once the avalanche enters the canyon it is travelling at maximum velocity (37 m/s) and is twice strongly deflected by the rock sidewalls. These impacts created a distinct linearly polarized seismic “avalanche transient” that had be used to time the destruction of the hotel. Concluding, the avalanche of Rigopiano detached at 15:41:59 (UTC), entered in a canyon (15:42:35), entrained trees and boulders - increasing the mass significantly - an hit the hotel on 15:43:20 at a speed of 100 km/h.Our results demonstrate that seismic recordings combined with simulations of mass movements are indispensable to remotely monitor snow avalanches.

Description: Published

Description: virtual meeting

Description: 7A. Geofisica per il monitoraggio ambientale

Description: The combination of rotational and traditional translational motion sensors already proofed to form a new technique in measuring seismic wave field properties. While the estimation of phase velocities of surface waves from regional to teleseismic earthquakes was done both using Love waves and also Rayleigh waves, it was shown just recently that using ambient noise will facilitate the estimation of phase velocity of Love waves by directly relating vertical translational motions to transverse acceleration using a simple plane wave assumption. Up to now, however, in the advent of sensitive, broad band rotational motion sensor these ambient noise based estimates were made only using arrays of traditional seismometer. These array derived rotation estimates on the other hand inherently show sever restrictions especially if the incoming wave field is not strictly planar. Having access to the first highly sensitive and broadband fibre optic gyro based rotational sensor, we performed several experiments at an active volcano as well as in an urban environment. We here present the result of a joint analysis of phase velocities of Love and Rayleigh waves which than are further combined with a classical H/V estimate in a velocity model for P- and S Waves. The application of this technique using data from a network of 6C sensor will help to increase the reliability of moment tensor inversions at active volcanoes as well as forming an easier to use extension of microzonation in densely populated areas.

Description: Published

Description: New Orleans

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

Description: The seismogenic role of transversal SW-NE striking faults in the inner Northern Apennines has recently gathered a renewed attention due to the occurrence of several M≈4 earthquakes the last of which occurred in May 2022. Many of these faults, however, do not show clear surface evidence even when releasing earthquakes and their recent and/or Quaternary evidence often a matter of discussion. For these reasons they can be extremely dangerous as they receive relatively little attention and are difficult to identify. We focus our attention on the integration of different datasets: seismic reflection profiles, surface kinematic data and the relocation of seismological data, to identify and characterize active faults whose dimension and earthquake potential would otherwise not be large enough to make them identifiable. We take as an example the Montespertoli NE-trending fault in southern Tuscany (central Italy) to which we associate the 2016 M=3.9 Castelfiorentino earthquake. This structure is part of a wider (in the order of 15–20 km) crustal-scale shear zone, which may be responsible for strong historical earthquakes of the area.

Description: Published

Description: Torino

Description: 4T. Sismicità dell'Italia

Description: The geothermal field of Torre Alfina is located in Central Italy, at the boundary between the regions Tuscany and Latium, at the northern extremity of the Vulsini quaternary volcanic complex. Geochemical and geophysical wells drilled in the 1970s and 1980s down to depths ranging from 563 m to 2710 m revealed that Torre Alfina is a medium- enthalpy (T = 140$\,^{\circ}$ C) geothermal field, hosted in buried fractured Mesozoic limestones. Recently a multi-national industrial company received the license for the production of geothermal energy up to a maximum of 5 MW. In 2013 the INGV was commissioned to realize a monitoring system that includes the observation of gas emissions, microseismicity and ground deformation. National guidelines published recently by the Italian Ministry of Economic Development (MISE) regulate in detail the governmental monitoring ordinances exclusively regarding the extraction of hydrocarbons and the fluid injection due to wastewater and CO2 storage but concerning geothermal energy production appropriate regulations are missing. Following the recommendations, described in the Ministerial Decree that regulates the geothermal production activity, the seismic monitoring system should be capable to record (i) the local microseismicity during the phase of geothermal energy production and (ii) the natural seismicity already 12 months before the beginning of the production operations. In 2014 we started to install a seismic network consisting of 5 short period stations within a radius of 5 km (Inner Domain) and thereafter further 5 stations inside an area with a 10 km radius (Outer Domain). The seismic noise level recorded at the single stations is unfavorably high, due to an intensive colonization and numerous settlements of small and medium industries. Transients as well as persistent monochromatic disturbances are recorded very well especially at the southern stations, probably due to a low wave energy dissipation inside the layer of quaternary volcanic rocks.

Description: Published

Description: Reno (Nevada)

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: Nach der Veröffentlichung des Positionspapiers des Forschungskollegiums Physik des Erdkörpers (FKPE) zur Induzierten Seismizität -- Milestone 1 (BAISCH et al. 2012), den Empfehlungen zur Diskriminierung induzierter Seismizität -- Milestone 2 (DAHM et al. 2013) und den Empfehlungen bezüglich der seismischen Gefährdung bei tiefengeothermischen Projekten -- Milestone 3 (BARTH et al. 2015) wurde auf der Sitzung der FKPE-Arbeitsgruppe Induzierte Seismizität (AGIS) vom November 2019 in Hannover die Notwendigkeit formuliert, ein entsprechendes Dokument für die Milestone-Gruppe 4 (Seismische Kontrollsysteme) vorzubereiten. Der vorliegende Artikel hat das Ziel, als Vergleich die im europäischen Ausland (Italien) gängige Best Practice mit einzubeziehen. Er bezieht sich vor allem auf die ministerialen Richtlinien von DIALUCE et al. (2014) und TERLIZZESE (2016) und den Artikel von BRAUN et al. (2019), in dem erste Anwendungen der italienischen Richtlinien (Italian Guidelines for monitoring the seismicity, underground deformation and pore pressure, ILG) zusammengestellt sind. In Italien begann die Diskussion über induzierte Seismizität unmittelbar nach den beiden tragischen Magnitude-6-Erdbeben in Emilia-Romagna im Mai 2012 (CESCA et al. 2013, BRAUN et al. 2018). Diese seismischen Ereignisse traten in einem tektonisch aktiven Gebiet mit ausgeprägter Erdöl- und Erdgasproduktion auf. Daher kam die Frage auf, inwieweit Förderaktivitäten Variationen im Spannungsfeld der Oberkruste verursachten, die die Erdbeben hätten auslösen können. Diese Vermutung wurde von DAHM et al. (2015) und JUANES et al. (2016) als extrem unwahrscheinlich eingestuft. Die nach den Emilia-Romagna-Ereignissen einberufene internationale Untersuchungskommission ICHESE (International Commission on Hydrocarbon Exploration and Seismicity in the Emilia Region) empfahl, sowohl die bestehenden als auch die zukünftigen Produktionsgebiete von Kohlenwasserstoffen und Geothermie mit modernen Netzwerken bezüglich der zeitlich-räumlichen Entwicklung der Seismizität, der Untergrunddeformation und des Porendrucks kontinuierlich zu überwachen. Eine vom italienischen Ministerium für wirtschaftliche Entwicklung (MiSE) einberufene nationale Arbeitsgruppe zur überwachung anthropogener Aktivitäten im Untergrund erstellte daraufhin Richtlinien (ILG, DIALUCE et al. 2014), insbesondere bezüglich der Förderung und Speicherung von Erdöl und Erdgas, der unterirdischen CO2-Speicherung sowie der Reinjektion von Lagerstättenwasser (wastewater). Um die ILG auch auf die Gewinnung von Erdwärme anwenden zu können, wurde nachfolgend vom MiSE eine auf die Geothermie angepasste Version veröffentlicht (TERLIZZESE 2016). Beide Fassungen beschreiben die Anforderungen an die überwachung anthropogener Aktivitäten im Untergrund in Bezug auf Seismizität, Deformation des Untergrundes und Porendruck. In Zukunft könnten die ILG außerdem auf weitere anthropogene Aktivitäten angewendet werden, beispielsweise auf die überwachung von Staudämmen, die Geothermie, die CO2-Speicherung, den Bergbau und Tunnelbohrungen.

Description: Published

Description: 5 - 9

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: N/A or not JCR

Description: This article describes the IT infrastructure implemented by the Centre for the Monitoring of Subsoil activities to monitor the areas of competence of which, according to the provisions of the Addresses and Guidelines and following the appointment by the Ministry for Economic Development, the INGV is the Structure in charge of seismic and geodetic Monitoring. Particular attention is paid to the hardware and software infrastructure, the data formats used and their installation is described.

Description: Published

Description: 1-32

Description: 3SR TERREMOTI - Attività dei Centri

Description: N/A or not JCR