scholarly journals Soil-gas survey of liquefaction and collapsed caves during the Emilia seismic sequence

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Alessandra Sciarra ◽  
Barbara Cantucci ◽  
Mauro Buttinelli ◽  
Gianfranco Galli ◽  
Manuela Nazzari ◽  
...  
Keyword(s):  
Soil Liquefaction ◽  
Early Pleistocene ◽  
Seismic Sequence ◽  
Alluvial Deposits ◽  
Epicentral Area ◽  
Emilia Romagna Region ◽  
External Part ◽  
Strength And Stiffness ◽  
Soil Measurements ◽  
Soil Gas Survey

<p>The epicentral area of the Emilia seismic sequence is located in the Emilia-Romagna Region (northern Italy), 45 km from the city of Modena (Figure 1). This area is sited within thrust-related folds of the Ferrara Arc, which represent the most external part of the northern Apennines. This sector is considered as having been active during late Pliocene to early Pleistocene times [Scrocca et al. 2007] and encompasses also the Mirandola and Ferrara seismogenic sources [e.g., Burrato et al. 2003, Boccaletti et al. 2004, Basili et al. 2008]. The main sedimentary infilling of the Po Plain is represented by Pliocene–Pleistocene alluvial deposits (alternating fluvial sands and clays) that overlie a foredeep clastic sequence, with a total average thickness of 2 km to 4 km [e.g., Carminati et al. 2010]. Soon after the mainshock, several liquefaction phenomena coupled to ground fractures were observed in the epicentral area (e.g., San Carlo, Ferrara). Soil liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. […] Collapsed caves reported in the literature and/or local press [e.g., Febo 1999, Martelli 2002] in the epicentral area were previously investigated by our research group in 2008, with several soil measurements of CO2 and CH4 fluxes. Immediately after the May 20, 2012, mainshock and during the Emilia seismic sequence, the collapsed caves were sampled again to determine any variations in these CO2 and CH4 fluxes. In this survey, newly formed collapsed caves were also found and measured (especially in the northern part of investigated area). […]</p>

scholarly journals Searching for the effects of the May-June 2012 Emilia seismic sequence (northern Italy): medium-depth deformation structures at the periphery of the epicentral area

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Lisa Borgatti ◽  
Antonio Edoardo Bracci ◽  
Stefano Cremonini ◽  
Giovanni Martinelli
Keyword(s):  
Ground Level ◽  
Northern Italy ◽  
Seismic Sequence ◽  
Surface Phenomena ◽  
Po River ◽  
Epicentral Area ◽  
Ground Fissures ◽  
Groundwater Levels ◽  
Geological Surveys ◽  
Emilia Romagna Region

<p>In 2012, a seismic sequence occurred in the lowlands of the Emilia-Romagna Region (northern Italy), between the borders of the Modena, Ferrara and Bologna Provinces. It consisted of seven mainshocks (5.9 &gt; Ml &gt; 5) that were recorded between May 20 and 29, 2012 [INGV 2012a] and 2,200 minor earthquakes [INGV 2012b]. An interferometric analysis [Bignami et al. 2012, Salvi et al. 2012, this volume] highlighted three main deformation areas, each of which was 12 km wide (from S to N) and 10 km to 20 km long in an ESE-WNW to E-W direction, thus affecting an area of about 600 km2 (Figure 1). Field and aerial geological surveys recorded numerous surficial effects, such as: (i) sediment liquefaction [Crespellani et al. 2012]; (ii) localized ground fissures resembling surficial faulting [Fioravante and Giretti 2012] (Figure 2); (iii) groundwater levels rising up to 400 cm above the local ground level in phreatic wells during the mainshocks (lower values were observed in confined aquifers); and (iv) dormancy of previously known sinkholes [Borgatti et al. 2010, Cremonini 2010a, and references therein]. Some of the observed surface phenomena were previously recorded as coseismic effects during the earthquakes of Ferrara (1570) and Argenta (1624) [Boschi et al. 1995, Galli 2000], together with the early rising of the water level of the Po River in the Stellata section. […]</p>

Soil Liquefaction During the Emilia, 2012 Seismic Sequence: Investigation and Analysis

2014 ◽  
pp. 1107-1110 ◽  
Author(s):  
Roberto W. Romeo ◽  
Sara Amoroso ◽  
Johann Facciorusso ◽  
Luca Lenti ◽  
Claudia Madiai ◽  
...  
Keyword(s):  
Soil Liquefaction ◽  
Seismic Sequence

scholarly journals Technologies and new approaches used by the INGV EMERGEO Working Group for real-time data sourcing and processing during the Emilia Romagna (northern Italy) 2012 earthquake sequence

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Giuliana Alessio ◽  
Laura Alfonsi ◽  
Carlo Alberto Brunori ◽  
Pierfrancesco Burrato ◽  
Giuseppe Casula ◽  
...  
Keyword(s):  
Seismic Event ◽  
Main Shock ◽  
Northern Italy ◽  
Earthquake Activity ◽  
Seismic Sequence ◽  
Time Data ◽  
Broad Area ◽  
Epicentral Area ◽  
Po Plain ◽  
Real Time Data

<p>On May 20, 2012, a Ml 5.9 seismic event hit the Emilia Po Plain, triggering intense earthquake activity along a broad area of the Po Plain across the provinces of Modena, Ferrara, Rovigo and Mantova (Figure 1). Nine days later, on May 29, 2012, a Ml 5.8 event occurred roughly 10 km to the SW of the first main shock. These events caused widespread damage and resulted in 26 victims. The aftershock area extended over more than 50 km and was elongated in the WNW-ESE direction, and it included five major aftershocks with 5.1 ≤Ml ≤5.3, and more than 2000 minor events (Figure 1). In general, the seismic sequence was confined to the upper 10 km of the crust. Minor seismicity with depths ranging from 10 km to 30 km extended towards the southern sector of the epicentral area (ISIDe, http://iside.rm.ingv.it/). […]</p><br />

scholarly journals The INGV real time strong motion data sharing during the 2016 Amatrice (central Italy) seismic sequence

2016 ◽  
Vol 59 ◽  
Author(s):  
Marco Massa ◽  
Ezio D'Alema ◽  
Chiara Mascandola ◽  
Sara Lovati ◽  
Davide Scafidi ◽  
...  
Keyword(s):  
Real Time ◽  
Data Sharing ◽  
Strong Motion ◽  
Main Task ◽  
Seismic Sequence ◽  
Web Portal ◽  
Epicentral Area ◽  
Strong Motion Data ◽  
Motion Data ◽  
The Web

<p><em>ISMD is the real time INGV Strong Motion database. During the recent August-September 2016 Amatrice, Mw 6.0, seismic sequence, ISMD represented the main tool for the INGV real time strong motion data sharing.  Starting from August 24<sup>th</sup>,  the main task of the web portal was to archive, process and distribute the strong-motion waveforms recorded  by the permanent and temporary INGV accelerometric stations, in the case of earthquakes with magnitude </em><em>≥</em><em> 3.0, occurring  in the Amatrice area and surroundings.  At present (i.e. September 30<sup>th</sup>, 2016), ISMD provides more than 21.000 strong motion waveforms freely available to all users. In particular, about 2.200 strong motion waveforms were recorded by the temporary network installed for emergency in the epicentral area by SISMIKO and EMERSITO working groups. Moreover, for each permanent and temporary recording site, the web portal provide a complete description of the necessary information to properly use the strong motion data.</em></p>

scholarly journals Neogene-Quaternary tectonic regime and macroseismic observations in the Tyrnavos-Elassona broader epicentral area of the March 2021, intense earthquake sequence

2021 ◽  
Vol 58 ◽  
pp. 200
Author(s):  
Dimitrios Galanakis ◽  
Sotiris Sboras ◽  
Garyfalia Konstantopoulou ◽  
Markos Xenakis
Keyword(s):  
Normal Fault ◽  
Fault Scarp ◽  
Focal Mechanisms ◽  
Fault System ◽  
Spatiotemporal Evolution ◽  
Surface Rupture ◽  
Alluvial Deposits ◽  
Epicentral Area ◽  
Ground Shaking ◽  
Macroseismic Observations

On March 3, 2021, a strong (Mw6.3) earthquake occurred near the towns of Tyrnavos and Elassona. One day later (March 4), a second strong (Mw6.0) earthquake occurred just a few kilometres toward the WNW. The aftershock spatial distribution and the focal mechanisms revealed NW-SE-striking normal faulting. The focal mechanisms also revealed a NE-SW oriented extensional stress field, different from the orientation we knew so far (ca. N-S). The magnitude and location of the two strongest shocks, and the spatiotemporal evolution of the sequence, strongly suggest that two adjacent fault segments were ruptured respectively. The sequence was followed by several coseismic ground deformational phenomena, such as landslides/rockfalls, liquefaction and ruptures. The landslides and rockfalls were mostly associated with the ground shaking. The ruptures were observed west of the Titarissios River, near to the Quaternary faults found by bore-hole lignite investigation. In the same direction, a fault scarp separating the alpidic basement from the alluvial deposits of the Titarissios valley implies the occurrence of a well-developed fault system. Some of the ground ruptures were accompanied by extensive liquefaction phenomena. Others cross-cut reinforced concrete irrigation channels without changing their direction. We suggest that this fault system was partially reactivated, as a secondary surface rupture, during the sequence as a steeper splay of a deeper low-to-moderate angle normal fault.

scholarly journals Brief communication: Co-seismic displacement on 26 and 30 October 2016 (<i>M</i><sub>w</sub> = 5.9 and 6.5) – earthquakes in central Italy from the analysis of a local GNSS network

2017 ◽  
Vol 17 (11) ◽  
pp. 1885-1892 ◽  
Author(s):  
Giorgio De Guidi ◽  
Alessia Vecchio ◽  
Fabio Brighenti ◽  
Riccardo Caputo ◽  
Francesco Carnemolla ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Central Italy ◽  
Geodetic Network ◽  
Satellite System ◽  
Fault System ◽  
Seismic Sequence ◽  
Epicentral Area ◽  
Seismic Displacement ◽  
Fault Trace ◽  
Global Navigation Satellite

Abstract. On 24 August 2016 a strong earthquake (Mw = 6.0) affected central Italy and an intense seismic sequence started. Field observations, DInSAR (Differential INterferometry Synthetic-Aperture Radar) analyses and preliminary focal mechanisms, as well as the distribution of aftershocks, suggested the reactivation of the northern sector of the Laga fault, the southern part of which was already rebooted during the 2009 L'Aquila sequence, and of the southern segment of the Mt Vettore fault system (MVFS). Based on this preliminary information and following the stress-triggering concept (Stein, 1999; Steacy et al., 2005), we tentatively identified a potential fault zone that is very vulnerable to future seismic events just north of the earlier epicentral area. Accordingly, we planned a local geodetic network consisting of five new GNSS (Global Navigation Satellite System) stations located a few kilometres away from both sides of the MVFS. This network was devoted to working out, at least partially but in some detail, the possible northward propagation of the crustal network ruptures. The building of the stations and a first set of measurements were carried out during a first campaign (30 September and 2 October 2016). On 26 October 2016, immediately north of the epicentral area of the 24 August event, another earthquake (Mw = 5.9) occurred, followed 4 days later (30 October) by the main shock (Mw = 6.5) of the whole 2016 summer–autumn seismic sequence. Our local geodetic network was fully affected by the new events and therefore we performed a second campaign soon after (11–13 November 2016). In this brief note, we provide the results of our geodetic measurements that registered the co-seismic and immediately post-seismic deformation of the two major October shocks, documenting in some detail the surface deformation close to the fault trace. We also compare our results with the available surface deformation field of the broader area, obtained on the basis of the DInSAR technique, and show an overall good fit.

scholarly journals Simulation of soil liquefaction due to earthquake loading

2019 ◽  
Vol 97 ◽  
pp. 03025 ◽  
Author(s):  
Armen Ter-Martirosyan ◽  
Ahmad Othman
Keyword(s):  
Los Angeles ◽  
Real Data ◽  
Soil Mass ◽  
Soil Liquefaction ◽  
Elastic Behavior ◽  
Main Step ◽  
Soil Behavior ◽  
The Difference ◽  
Strength And Stiffness ◽  
Seismic Impact

Liquefaction is a phenomenon in which the strength and stiffness of a soil are reduced as a result of seismic or other dynamic effects. Liquefaction was the main reason of the huge damages caused by many earthquakes around the world. The modeling of soil behavior is the main step in the process of predicting the soil liquefaction. Currently, a large number of soil models are presented. However, only some of them can simulate this process. One of these models which can be used is model UBC3D-PLM. In this paper, the possibilities of this model are considered by modeling the seismic impact on a building with its different heights on the PLAXIS software package. The real data of Upland earthquake 1990 near Los Angeles city was used. Results of the simulation showed the difference in the behavior of the soil mass under the influence of an earthquake compared with the elastic behavior, as well as the need to use the UBC3D-PLM model to estimate the seismic impact.

Seismic Performance of Industrial Sheds and Liquefaction Effects During May 2012 Emilia Earthquakes Sequence in Northern Italy

2014 ◽  
Vol 08 (02) ◽  
pp. 1450009 ◽  
Author(s):  
Gian Paolo Cimellaro ◽  
Marco Chiriatti ◽  
Hwasung Roh ◽  
Andrei M. Reinhorn
Keyword(s):  
Emergency Response ◽  
Working Hours ◽  
Northern Italy ◽  
Seismic Sequence ◽  
Epicentral Area ◽  
Existing Structures ◽  
Industrial Sites ◽  
Emilia Earthquake ◽  
Private Homes ◽  
Seismic Area

On May 20, 2012 at 2:03 UTC, a Mw 6.1 earthquake occurred in Emilia Region of Northern Italy. The event was preceded by a Ml 4.1 foreshock on May 19, 2012 at 23:13 UTC, and followed by several aftershocks, twenty of them with a magnitude Mw greater than 4. The epicentral area of the seismic sequence covers alluvial lowland that is occupied by both agricultural and urbanized areas. Liquefaction effects were observed in several villages on the west side of Ferrara which were built upon former river beds such as the Reno River. The Emilia seismic sequence resulted in 27 casualties, several of whom were among the workers in the factories that collapsed during working hours, and there was extensive damage to monuments, public buildings, industrial sites and private homes. Almost no municipalities hit by 2012 earthquake were classified as seismic area before 2003; therefore, most of the existing structures had been designed without taking in account the seismic actions. The main aims of MCEER field mission was to document the emergency response and the most common damage mechanisms of industrial sheds during Emilia earthquake sequence which are shown and discussed in detail.

scholarly journals The Pollino 2012 seismic sequence: clues from continuous radon monitoring

2016 ◽  
Author(s):  
Antonio Piersanti ◽  
Valentina Cannelli ◽  
Gianfranco Galli
Keyword(s):  
Seismic Energy ◽  
Detection Algorithm ◽  
Change Point Analysis ◽  
Radon Emanation ◽  
Seismic Sequence ◽  
Epicentral Area ◽  
Quantitative Evidence ◽  
The Impact ◽  
Radon Monitoring

Abstract. The 2012 Pollino (Calabria, Italy) seismic sequence, culminating in the Mw 5.2 earthquake of October 25, 2012, is investigated exploiting data collected during a long term continuous radon monitoring experiment performed in the epicentral area from late 2011 to the end of 2014. We analyze data collected both using a phenomenological approach based on quantitative evidence and a purely numerical analysis including: i) correlation and cross-correlation investigations; ii) an original approach aimed to limit the impact of meteorological parameters variations on the interpretation of measured radon levels; iii) a change point analysis; iv) the implementation of an original detection algorithm aimed to highlight the connections between radon emission variations and major seismic events occurrence. Results from both approaches suggest that radon monitoring stations can be subject to massive site effects, especially regarding rainfall, making data interpretation harder. The availability of long term continuous measurements is crucial to precisely assess those effects. Nevertheless, statistical analysis shows a viable approach for quantitatively relating radon emanation variations to seismic energy release. Although much work is still needed to make radon timeseries analysis a robust complement to traditional seismological tools, this work has identified a characteristic variation in radon exhalation during the preparation process of large earthquakes.

scholarly journals Soil gas geochemical behaviour across buried and exposed faults during the 24 august 2016 central Italy earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Giancarlo Ciotoli ◽  
Alessandra Sciarra ◽  
Livio Ruggiero ◽  
Aldo Annunziatellis ◽  
Sabina Bigi
Keyword(s):  
Active Fault ◽  
Central Italy ◽  
Soil Gas ◽  
Seismic Sequence ◽  
Spatial Behaviour ◽  
Fault Rupture ◽  
Central Italy Earthquake ◽  
Geochemical Behaviour ◽  
Buried Fault ◽  
Soil Gas Survey

<p>Following the earthquake (M<sub>L</sub>=6.0) of 24 August 2016 that affected large part of the central Apennine between the municipalities of Norcia (PG) and Amatrice (RI) (central Italy), two soil gas profiles (i.e., <sup>222</sup>Rn, <sup>220</sup>Rn, CO<sub>2</sub> and CO<sub>2</sub> flux) were carried out across buried and exposed coseismic fault rupture of the Mt. Vettore fault during the seismic sequence. The objective of the survey was to explore the mechanisms of migration and the spatial behaviour of different gas species near still-degassing active fault. Results provide higher gas and CO<sub>2</sub> flux values (about twice for <sup>222</sup>Rn and CO<sub>2</sub> flux) in correspondence of the buried sector of the fault than those measured across the exposed coseismic rupture. Anomalous peaks due to advective migration are clearly visible on both side of the buried fault (profile 1), whereas the lower soil gas concentrations measured across the exposed coseimic rupture (profile 2) are mainly caused by shallow and still acting diffusive degassing associated to faulting during the seismic sequence. These results confirm the usefulness of the soil gas survey to spatially recognise the shallow geometry of hidden faults, and to discriminate the geochemical migration mechanisms occurring at buried and exposed faults related to seismic activity.</p>

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