Online Material: Seismic‐hazard map, figures of event location and waveforms, phase reading distribution, and background seismic noise; and tables of event parameters, 1D regional model, and earthquake catalog.
The Collalto Seismic Network (Rete Sismica di Collalto, or RSC) is the infrastructure used to monitor the natural and induced seismicity of the natural gas storage concession known as Collalto Stoccaggio, which is located in northeastern Italy. This network was realized and is currently managed by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), a public research institute, on behalf of Edison Stoccaggio S.p.A., the storage concession holder.
The storage exploits a depleted natural gas reservoir that was converted into a seasonal reservoir in the 1990s. The reservoir is a geologic trap, with porous and permeable rock layers, a few meters thick, sealed by impermeable formations. The production levels are located at 1500–1600 m depth (Picotti, 2007) and extend approximately over a 10 km×4 km wide area (Fig. 1). The gas storage activity affects four municipalities, all of which are located in the province of Treviso: Susegana, Nervesa della Battaglia, S. Pietro di Feletto, and Conegliano.
Figure 1.
Location of the study area, including the Collalto Seismic Network (RSC). Seismometric stations are indicated by triangles; the 10 RSC stations by white triangles (labels start with ED; all are located within area A); and the stations of the Northeastern Italy Integrated Seismic Network (NEI) by black triangles, respectively. All the stations indicated are managed by the OGS. The two rectangles bordered by thin lines indicate the two target areas, A and B. The irregular area bordered by a thick black line within area A corresponds to the surface projection of the gas storage reservoir. The fault lines indicate the active faults known for the study area according to Poli et al. (2008). Insets (a) and (b) …
The present work concerns seismic data acquisition and elaboration of a more than two-year period (February 2006 - June 2008). These data have been recorded by a micro seismic network of four stations, installed between March 2005 and January 2008 close to the outlet of Cellina River into the Friulian plain, north of Pordenone (Friuli Venezia Giulia). The main subjects concern earthquake identification, their location and magnitude calculation.
Abstract. Thanks to the installation of a temporary seismic network, a microseismicity study has been conducted in the Sulmona area (Abruzzo, Italy) with the aim of increasing the knowledge of seismogenic potential of existing active faults. In this work the first seven months (from 27 May to 31 December 2009) of recorded data have been analysed, over a total period of acquisition of about 30 months. Using a semi-automatic procedure, more than 800 local earthquakes has been detected, which highlight the background seismicity previously unknown. About 70% of these events have been relocated using a 1-D velocity model estimated specifically for the Sulmona area. Phase readings quality is checked and discussed, with respect to weighting schemes used by location algorithms, too. The integration of temporary network data with all the other data available in the region enable us to obtain a statistically more robust dataset of earthquake locations. Both the final hypocentral solutions and phase pickings are released as online Supplement. Local magnitude values of the newly detected events ranges between −1.5 and 3.7 and the completeness magnitude for the Sulmona area during the study period is about 1.1. Duration magnitude coefficients have been estimated as well, for comparison/integration purposes. Local Gutenberg–Richter relationship, estimated from the microseismic data, features low b value, possibly suggesting that the Sulmona area is currently undergoing high stress, in agreement with other recent studies. The time-space distribution of the seismic activity with respect to the known active faults, as well the seismogenic layer thickness, are preliminarily investigated.
Abstract. We analyse the instrumental seismicity in a sector of the Po Plain (Italy) with the aim of defining the baseline for seismic monitoring of a new underground gas storage plant that will use the depleted gas reservoir of Cornegliano Laudense, near Lodi. The target area – a square approximately 80 x 80 km wide – is commonly considered aseismic. The analysed period, 1951–2019, includes all available instrumental data. We gathered the P- and S-phase readings collected by various agencies for more than 300 events, approximately located inside the target area. We processed the earthquakes in a uniform way, using absolute location algorithms and velocity models adopted by the regional and national monitoring networks. The relocated earthquake dataset depicts an image of weak and deep seismicity for this central sector of the Po Plain, which is quite different from the initial one derived from the existing earthquake catalogues. Within a distance of approximately 30 km from Lodi, earthquakes are extremely rare (on average 0.5 earthquake/yr, assuming a completeness magnitude Mc = 2.7 from the 1980s); only 2 weak events fall at less than 15 km distance from the reservoir in the whole period 1951–2019. The strongest events instrumentally recorded are related to the seismic sequence of Caviaga in 1951 that represent the first instrumental recordings for that area. Confirming the hypocentral depths recently proposed by Caciagli et al., 2015, the events are far from the gas reservoir; we suggest a common tectonic stress of the main shock of 1951 and the M4.2 earthquake of Dec 17, 2020, on the basis of the similarities in depth, location and focal mechanism. While it is clear that the deep seismicity corresponds to the collision between the Northern Apennine and Southern Alps, it is much less clear, however, which geological structures are capable of generating earthquakes. Our results and the improvement in the observational capabilities of the very last years will help refining the seismogenic sources hypothesized for this area.
In this paper we evaluate the local seismic response for thirteen sites located in the municipalities of Arquata del Tronto and Montegallo, two areas which suffered heavy damage during the Mw 6.0 and Mw 5.4 earthquakes which struck Central Italy on August 24, 2016. The input dataset is made by ground motion recordings of 348 events occurred during the sequence. The spectral site response is estimated by the Generalized Inversion Technique and makes use of reference sites. The interpretation is further improved through the information provided by a reference-site independent method (i.e., the so called Receiver-Function Technique) and by the Horizontal-to-Vertical Spectral Ratios of ambient noise recordings. We also provide an independent estimate of the local amplification by comparing the Peak Ground Velocity and the Spectral Amplitudes observed at each site to the value estimated by well-established Ground Motion Prediction Equations for a rock-class site. The results obtained by the adopted methodologies are all highly consistent, and they emphasize the different seismic behavior of several sites at local scale. Thus, sites located on Quaternary deposits overlying the bedrock, such as Castro, Pretare, Spelonga, Pescara del Tronto, and Capodacqua feature some relevant amplifications in a medium (2–10 Hz) frequency range; two sites at Spelonga show amplifications also at low frequencies; three sites located on stiff formations, i.e. Uscerno, Balzo and Colle d'Arquata, respectively, feature either nearly neutral response or low amplification level. A probable topographic effect was identified at the rock site of Rocca di Arquata (MZ80).
Abstract. Thanks to the installation of a temporary seismic network, a microseismicity study has been conducted in the Sulmona area (Abruzzo, Italy) with the aim of increasing the knowledge of seismogenic potential of existing active faults. In this work the first 7 months (from 27 May to 31 December 2009) of recorded data have been analysed over a total period of acquisition of about 30 months. Using a semi-automatic procedure, more than 800 local earthquakes have been detected, which highlights the previously unknown background seismicity. About 70% of these events have been relocated using a 1-D velocity model estimated specifically for the Sulmona area. The integration of temporary network data with all the other data available in the region enables us to obtain a statistically more robust data set of earthquake locations. Both the final hypocentral solutions and phase pickings are released as a supplement; an appendix also describes phase readings' quality with respect to weighting schemes used by location algorithms. Local magnitude values of the newly detected events range between −1.5 and 3.7 and the completeness magnitude for the Sulmona area during the study period is about 1.1. Duration magnitude coefficients have been estimated as well for comparison/integration purposes. The local Gutenberg–Richter relationship, estimated from the microseismic data, features a low b value, tentatively suggesting that the Sulmona area may be currently undergoing high-stress conditions, in agreement with other recent studies. The time–space distribution of the seismic activity with respect to the known active faults as well the seismogenic layer thickness are preliminarily investigated.
Research Article| May 29, 2019 Microseismic Portrait of the Montello Thrust (Southeastern Alps, Italy) from a Dense High‐Quality Seismic Network Maria Adelaide Romano; Maria Adelaide Romano Corresponding Author aCentro Ricerche Sismologiche (CRS), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante, 42/C, 34010 Sgonico (TS), Italy, aromano@inogs.it Search for other works by this author on: GSW Google Scholar Laura Peruzza; Laura Peruzza aCentro Ricerche Sismologiche (CRS), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante, 42/C, 34010 Sgonico (TS), Italy, aromano@inogs.it Search for other works by this author on: GSW Google Scholar Marco Garbin; Marco Garbin bCentro Ricerche Sismologiche (CRS), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Via Treviso, 55, 33100 Cussignacco (UD), Italy Search for other works by this author on: GSW Google Scholar Enrico Priolo; Enrico Priolo aCentro Ricerche Sismologiche (CRS), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante, 42/C, 34010 Sgonico (TS), Italy, aromano@inogs.it Search for other works by this author on: GSW Google Scholar Vincenzo Picotti Vincenzo Picotti cDepartment of Earth Sciences, Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2019) 90 (4): 1502–1517. https://doi.org/10.1785/0220180387 Article history first online: 29 May 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Maria Adelaide Romano, Laura Peruzza, Marco Garbin, Enrico Priolo, Vincenzo Picotti; Microseismic Portrait of the Montello Thrust (Southeastern Alps, Italy) from a Dense High‐Quality Seismic Network. Seismological Research Letters 2019;; 90 (4): 1502–1517. doi: https://doi.org/10.1785/0220180387 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT The Montello thrust is part of a complex system of the active southeastern front of the Alps in northeastern Italy. An underground gas‐storage facility operates in the anticline at the hanging wall of this thrust system. The Collalto Seismic Network was designed to monitor the induced microseismicity and natural earthquakes around this storage. We analyzed the first 6 yr seismic catalog, containing 1635 earthquakes with −0.8≤ML≤4.5 localized with an enhanced 1D velocity model. The clearly aligned seismicity pattern depicts the Montello thrust as an ∼1000 km2 plane, gently dipping to the northwest and locally interrupted by high‐angle faults, which are nearly perpendicular to the main plane. The observed seismicity suggests a creeping behavior of the main thrust at seismogenic depth (5–13 km). However, we cannot exclude the possibility some parts of the system not microseismically active might be locked and under loading stress condition. Finally, we did not observe a space–time correlation between the microseismicity and the anthropogenic activity occurring in the reservoir. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Abstract. We analysed the instrumental seismicity in a sector of the Po Plain (Italy) to define the baseline for seismic monitoring of a new underground gas storage plant that will use the depleted gas reservoir of Cornegliano Laudense, near Lodi. The target area – a square approximately 80 km × 80 km wide – is commonly considered aseismic. The analysed period, 1951–2019, includes all available instrumental data. We gathered the P- and S-phase readings collected by various agencies for more than 300 events, approximately located inside the target area. We processed the earthquakes uniformly, using absolute location algorithms and velocity models adopted by the regional and national monitoring networks. The relocated earthquake dataset depicts an image of weak and deep seismicity for this central sector of the Po Plain, which is quite different from the initial one derived from the existing earthquake catalogues. Within a distance of approximately 30 km from Lodi, earthquakes are extremely rare (on average 0.5 earthquakes per year, assuming a completeness magnitude Mc = 2.7 from the 1980s); only two weak events fall at less than 15 km distance from the reservoir in the whole period 1951–2019. The strongest events instrumentally recorded are related to the seismic sequence of Caviaga in 1951 that represent the first instrumental recordings for that area. Confirming the hypocentral depths recently proposed by Caciagli et al. (2015), the events are far from the gas reservoir; we suggest common tectonic stress of the main shock of 1951 and the M4.2 earthquake of 17 December 2020, based on the similarities in depth, location, and focal mechanism. While it is clear that the deep seismicity corresponds to the collision between the Northern Apennines and the Southern Alps, the characterization of the geological structures that generate earthquakes appears uncertain. Our results are a preliminary benchmark for the definition of seismogenic zones in the Lodi area, whose definition can be improved with the existing observational capabilities now available in the surroundings.
Seismic catalogues (QuakeML format) of a microearthquake sequence occurred on August 2021 in the Montello thrust area and recorded by the Collalto seismic network (10.7914/SN/EV); the seismic catalogues are provided, separately, for different earthquake location codes (h71=Hypo71; hel=Hypoellipse; hypoDD=HypoDD; migraloc=Migraloc). DATA_tgz_SAC.tar contains earthquake waveforms (SAC format) with P and S arrival times used for the locations. Other details in Peruzza et al. (2022, doi: 10.3389/feart.2022.1044296).
Abstract In this article, we describe the infrastructure developed and managed by the Italian National Institute of Oceanography and Applied Geophysics – OGS for the seismological and geodetic monitoring of northeastern Italy. The infrastructure was constituted in response to the ML 6.4 Friuli destructive earthquake of 1976, with the main mandate of supporting civil protection emergency activities. The OGS monitoring infrastructure is presently composed of a seismometric and a strong-motion network, complemented by a number of Global Navigation Satellite Systems stations, each delivering observational data in real time, which are collected and processed by the headquarters of the Center for Seismological Research of OGS in Udine. The OGS networks operate in close cooperation with Italian and international networks from neighboring countries, within the framework of the agreements for real-time data exchange, to obtain improved rapid earthquake location and magnitude estimations. Information regarding seismic events is released to the public through a dedicated web portal and, since 2013, through social media. Aside from the standard monitoring activities (>30,000 events have been recorded since 1976), the OGS has progressively increased the number of services to the public and to the Civil Protection of the Friuli Venezia Giulia and Veneto regions. The high availability of good quality data has resulted in the enhancement of scientific products, including advanced seismological studies of the area, spanning broadly from seismic source characterization to engineering seismology. In the future, the OGS networks are expected to further contribute to the development of seismological research and monitoring infrastructures of the Central European region.
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