Petrinja M6.2 earthquake (Croatia) on 29/12/2020 occurred on the intersection of the two regional active faults at the transition between Dinarides and Pannonian basin

2021 ◽  
Author(s):  
Tvrtko Korbar ◽  
Matija Vukovski ◽  
Snježana Markušić
Keyword(s):  
Pannonian Basin ◽  
Active Faults ◽  
Focal Depth ◽  
Fault System ◽  
Geophysical Research ◽  
Epicentral Area ◽  
Gps Velocities ◽  
Banja Luka ◽  
Adriatic Region ◽  
External Dinarides

<p>Devastating M6.2 earthquake (1) hit Petrinja epicentral area (2) on 2020-12-29. M5.0 foreshock on 2020-12-28 (1) caused moderate damage on buildings and forced many inhabitants to move out form their homes. Thus, the foreshock was a kind of lucky event that saved many human lives.</p><p>Considering the shallow focal depth (1) and QMTS that show clear strike-slip focal mechanisms (3, 4), surface failures were expected after the mainshock. Immediate reports in media allowed quick online research of surface failures indicating that linear infrastructure damages appear along ~30 km long portion of sinistral NE-SW striking Sisak-Petrinja-Glina-Topusko Fault. Quick field inspection revealed that fresh fault planes in the bedrock appear mostly along longitudinal NW-SE striking (Dinaric strike) Pokupsko-Kostajnica-Banja Luka Fault, and show clear dextral co-seismic stike-slip displacements. The map view time-lapse animation of the seismic sequence (5) revealed that ~20 km long portion of the Pokupsko Fault was (re)activated. The two subvertical  mutually perpendicular faults intersect near the epicenters. The historically important Pokupsko earthquake occured in the vicinity (6), and was used by a famous Croatian geophysicist Andrija Mohorovičić to discover the MOHO discontinuity.</p><p>The fault system is textbook example of major failure in the upper crust along the pre-existing fault net (7) at the critical moment of centennial release of generally north-south oriented compressional strain that is accumulating in the crust because of continuous northward movement of the Adriatic microplate (Adria). Up to 10 mm/yr Adria GPS velocities measured in the Adriatic foreland are mostly accommodating along major External Dinarides active faults, since the Internal Dinarides GPS velocities are only 1-2 mm/yr, while the velocities in the Pannonian basin are near zero (8). The dextral Pokupsko-Banja Luka Fault could be one of the main inherited active faults between the crustal segments of the Adria, while sinistral Petrinja fault could represent reactivated Mesozoic transform fault bordering the crustal fragments (9) of once greater Adria (10).</p><ul><li>(1) https://www.pmf.unizg.hr/geof/seizmoloska_sluzba, Accessed: 2020-12-29 11:50 UTC</li> <li>(2) Stanko D, Markušić S, Korbar T, Ivančić J. (2020): Estimation of the High-Frequency Attenuation Parameter Kappa for the Zagreb (Croatia) Seismic Stations. Applied Sciences. 10(24):8974.</li> <li>(3) https://www.emsc-csem.org/#2, Accessed: 2020-12-28 05:28:07 UTC</li> <li>(4) https://www.emsc-csem.org/#2, Accessed: 2020-12-29 11:35 UTC</li> <li>(5) https://www.pmf.unizg.hr/geof/seizmoloska_sluzba, Accessed: 2021-01-03 07:50 UTC</li> <li>(6) Herak, D and Herak, M. (2010): The Kupa Valley (Croatia) earthquake of 8 October 1909 – 100 years later. Seismological research letters, 81, 30-36.</li> <li>(7) Pikija, M. (1987): Osnovna geološka karta SFRJ, 1: 100 000: List Sisak, L 33-93. hgi-cgs.hr</li> <li>(8) Battaglia, M., Murray, M.H., Serpelloni, E. and Bürgmann, R. (2004). The Adriatic region: An independent microplate within the Africa-Eurasia collision zone. Geophysical Research Letters, 31, 1–4.</li> <li>(9) Korbar (2009): Orogenic evolution of the External Dinarides in the NE Adriatic region: a model constrained by tectonostratigraphy of Upper Cretaceous to Paleogene carbonates. Earth Science Reviews, 96/4, 296-312.</li> <li>(10) van Hinsbergen, D.J.J., Torsvik, T.H., Schmid, S.M., Maţenco, L.C., Maffione, M., Vissers, R.L.M., Gürer, D., Spakman, W. (2020): Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic. Gondwana Research, 81, 79-229.</li> </ul>

Joint multidisciplinary study of the Saint-Sauveur–Donareo fault (lower Var valley, French Riviera): a contribution to seismic hazard assessment in the urban area of Nice

2011 ◽  
Vol 182 (4) ◽  
pp. 323-336 ◽  
Author(s):  
Christophe Larroque ◽  
Bertrand Delouis ◽  
Jean-Claude Hippolyte ◽  
Anne Deschamps ◽  
Thomas Lebourg ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Urban Areas ◽  
Regional Scale ◽  
Active Faults ◽  
Focal Depth ◽  
Strike Slip ◽  
Fault System ◽  
Geophysical Investigation ◽  
Lateral Strike Slip ◽  
North East

AbstractThe lower Var valley is the only large outcropping zone of Plio-Quaternary terrains throughout the southwestern Alps. In order to assess the seismic hazard for the Alps – Ligurian basin junction, we investigated this area to provide a record of earthquakes that have recently occurred near the city of Nice. Although no historical seismicity has been indicated for the lower Var valley, our main objective was to identify traces of recent faulting and to discuss the seismogenic potential of any active faults. We organized multidisciplinary observations as a microseismic investigation (the PASIS survey), with morphotectonic mapping and imagery, and subsurface geophysical investigations. The results of the PASIS dense recording survey were disappointing, as no present-day intense microseismic activity was recorded. From the morphotectonic investigation of the lower Var valley, we revealed several morphological anomalies, such as drainage perturbations and extended linear anomalies that are unrelated to the lithology. These anomalies strike mainly NE-SW, with the major Saint-Sauveur – Donareo lineament, clearly related to faulting of the Plio-Pleistocene sedimentary series. Sub-surface geophysical investigation (electrical resistivity tomography profiling) imaged these faults in the shallow crust, and together with the microtectonic data, allow us to propose the timing of recent faulting in this area. Normal and left-lateral strike-slip faulting occurred several times during the Pliocene. From fault-slip data, the last episode of faulting was left-lateral strike-slip and was related to a NNW-SSE direction of compression. This direction of compression is consistent with the present-day state of stress and the Saint-Sauveur–Donareo fault might have been reactivated several times as a left-lateral fault during the Quaternary. At a regional scale, in the Nice fold-and-thrust belt, these data lead to a reappraisal of the NE-SW structural trends as the major potentially active fault system. We propose that the Saint-Sauveur–Donareo fault belongs to a larger system of faults that runs from near Villeneuve-Loubet to the southwest to the Vésubie valley to the north-east. The question of a structural connection between the Vésubie – Mt Férion fault, the Saint-Sauveur–Donareo fault and its possible extension offshore through the northern Ligurian margin is discussed.The Saint-Sauveur–Donareo fault shows two en-échelon segments that extend for about 8 km. Taking into account the regional seismogenic depth (about 10 km), this fault could produce M ~6 earthquakes if activated entirely during one event. Although a moderate magnitude generally yields a moderate seismic hazard, we suggest that this contribution to the local seismic risk is high, taking into account the possible shallow focal depth and the high vulnerability of Nice and the surrounding urban areas.

scholarly journals Destructive M6.2 Petrinja Earthquake (Croatia) in 2020—Preliminary Multidisciplinary Research

2021 ◽  
Vol 13 (6) ◽  
pp. 1095
Author(s):  
Snježana Markušić ◽  
Davor Stanko ◽  
Davorin Penava ◽  
Ines Ivančić ◽  
Olga Bjelotomić Oršulić ◽  
...  
Keyword(s):  
Peak Ground Acceleration ◽  
Pannonian Basin ◽  
Fault System ◽  
Earthquake Ground Motion ◽  
Ground Acceleration ◽  
Epicentral Area ◽  
Local Site ◽  
Site Characteristics ◽  
Complex Fault ◽  
Collapsed Buildings

On 28 December 2020, seismic activity in the wider Petrinja area strongly intensified after a period of relative seismological quiescence that had lasted more than 100 years (since the well-known M5.8 Kupa Valley earthquake of 1909, which is known based on the discovery of the Mohorovičić discontinuity). The day after the M5 foreshock, a destructive M6.2 mainshock occurred. Outcomes of preliminary seismological, geological and SAR image analyses indicate that the foreshocks, mainshock and aftershocks were generated due to the (re)activation of a complex fault system—the intersection of longitudinal NW–SE right-lateral and transverse NE–SW left-lateral faults along the transitional contact zone of the Dinarides and the Pannonian Basin. According to a survey of damage to buildings, approximately 15% of buildings were very heavily damaged or collapsed. Buildings of special or outstanding historical or cultural heritage significance mostly collapsed or became unserviceable. A preliminary analysis of the earthquake ground motion showed that in the epicentral area, the estimated peak ground acceleration PGA values for the bedrock ranged from 0.29 to 0.44 g. In the close Petrinja epicentral area that is characterized by the superficial deposits, significant ground failures were reported within local site effects. Based on that finding and building damage, we assume that the resulting peak ground acceleration (PGAsite) values were likely between 0.4 and 0.6 g depending on the local site characteristics and the distance from the epicentre.

scholarly journals Rapid response to the Mw 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

2020 ◽  
Author(s):  
Cécile Cornou ◽  
Jean-Paul Ampuero ◽  
Coralie aubert ◽  
Laurence Audin ◽  
Stéphane Baize ◽  
...  
Keyword(s):  
Focal Depth ◽  
Seismic Hazard Assessment ◽  
Normal Fault ◽  
Field Evaluation ◽  
Fault System ◽  
Seismic Unit ◽  
Epicentral Area ◽  
Massif Central ◽  
Moderate Seismicity ◽  
Rhone Valley

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude,  and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations),  geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics.

scholarly journals Joint Interpretation of Geophysical Results and Geological Observations for Detecting Buried Active Faults: The Case of the “Il Lago” Plain (Pettoranello del Molise, Italy)

2021 ◽  
Vol 13 (8) ◽  
pp. 1555
Author(s):  
Rosa Nappi ◽  
Valeria Paoletti ◽  
Donato D’Antonio ◽  
Francesco Soldovieri ◽  
Luigi Capozzoli ◽  
...  
Keyword(s):  
Seismic Tomography ◽  
Active Faults ◽  
Low Frequency ◽  
Normal Fault ◽  
Seismic Source ◽  
Fault System ◽  
Normal Faults ◽  
Macroseismic Data ◽  
Epicentral Area ◽  
Seismogenic Source

We report a geophysical study across an active normal fault in the Southern Apennines. The surveyed area is the “Il Lago” Plain (Pettoranello del Molise), at the foot of Mt. Patalecchia (Molise Apennines, Southern Italy), a small tectonic basin filled by Holocene deposits located at the NW termination of the major Quaternary Bojano basin structure. This basin, on the NE flank of the Matese Massif, was the epicentral area of the very strong 26 July, 1805, Sant’Anna earthquake (I0 = X MCS, Mw = 6.7). The “Il Lago” Plain is bordered by a portion of the right-stepping normal fault system bounding the whole Bojano Quaternary basin (28 km long). The seismic source responsible for the 1805 earthquake is regarded as one of the most hazardous structures of the Apennines; however, the position of its NW boundary of this seismic source is debated. Geological, geomorphological and macroseismic data show that some coseismic surface faulting also occurred in correspondence with the border fault of the “Il Lago” Plain. The study of the “Il Lago” Plain subsurface might help to constrain the NW segment boundary of the 1805 seismogenic source, suggesting that it is possibly a capable fault, source for moderate (Mw < 5.5) to strong earthquakes (Mw ≥ 5.5). Therefore, we constrained the geometry of the fault beneath the plain using low-frequency Ground Penetrating Radar (GPR) data supported by seismic tomography. Seismic tomography yielded preliminary information on the subsurface structures and the dielectric permittivity of the subsoil. A set of GPR parallel profiles allowed a quick and high-resolution characterization of the lateral extension of the fault, and of its geometry at depth. The result of our study demonstrates the optimal potential of combined seismic and deep GPR surveys for investigating the geometry of buried active normal faults. Moreover, our study could be used for identifying suitable sites for paleoseismic analyses, where record of earthquake surface faulting might be preserved in Holocene lacustrine sedimentary deposits. The present case demonstrates the possibility to detect with high accuracy the complexity of a fault-zone within a basin, inferred by GPR data, not only in its shallower part, but also down to about 100 m depth.

Neotectonics of the Dinarides–Pannonian Basin transition and possible earthquake sources in the Banja Luka epicentral area

2014 ◽  
Vol 82 ◽  
pp. 52-68 ◽  
Author(s):  
Kamil Ustaszewski ◽  
Marijan Herak ◽  
Bruno Tomljenović ◽  
Davorka Herak ◽  
Srebrenka Matej
Keyword(s):  
Pannonian Basin ◽  
Epicentral Area ◽  
Earthquake Sources ◽  
Banja Luka

Bathymetry and uplift rate of the Gulf of Aqaba, Dead Sea Fault.

2021 ◽  
Author(s):  
Matthieu Ribot ◽  
Yann Klinger ◽  
Edwige Pons-Branchu ◽  
Marthe Lefevre ◽  
Sigurjón Jónsson
Keyword(s):  
High Resolution ◽  
Tectonic Evolution ◽  
Active Faults ◽  
Major Change ◽  
Dead Sea ◽  
Fault System ◽  
Arabian Plate ◽  
Gulf Of Aqaba ◽  
Uplift Rate ◽  
The Dead

&lt;p&gt;Initially described in the late 50&amp;#8217;s, the Dead Sea Fault system connects at its southern end to the Red Sea extensive system, through a succession of left-stepping faults. In this region, the left-lateral differential displacement of the Arabian plate with respect to the Sinai micro-plate along the Dead Sea fault results in the formation of a depression corresponding to the Gulf Aqaba. We acquired new bathymetric data in the areas of the Gulf of Aqaba and Strait of Tiran during two marine campaigns (June 2018, September 2019) in order to investigate the location of the active faults, which structure and control the morphology of the area. The high-resolution datasets (10-m posting) allow us to present a new fault map of the gulf and to discuss the seismic potential of the main active faults.&lt;/p&gt;&lt;p&gt;We also investigated the eastern margin of the Gulf of Aqaba and Tiran island to assess the vertical uplift rate. To do so, we computed high-resolution topographic data and we processed new series of U-Th analyses on corals from the uplifted marine terraces.&lt;/p&gt;&lt;p&gt;Combining our results with previous studies, we determined the local and the regional uplift in the area of the Gulf of Aqaba and Strait of Tiran.&lt;/p&gt;&lt;p&gt;Eventually, we discussed the tectonic evolution of the gulf since the last major change of the tectonic regime and we propose a revised tectonic evolution model of the area.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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 Empirical Relationship for Assessing the Near-Field Horizontal Coseismic Displacement Using GPS Seismology Data

2021 ◽  
Vol 60 (1) ◽  
pp. 31-50
Author(s):  
Ryad Darawcheh ◽  
Riad Al Ghazzi ◽  
Mohamad Khir Abdul-wahed
Keyword(s):  
Near Field ◽  
Empirical Relationship ◽  
Active Faults ◽  
Historical Earthquakes ◽  
Dead Sea ◽  
Fault System ◽  
Coseismic Displacement ◽  
Data Set ◽  
Earthquake Parameters ◽  
Gps Station

In this research, a data set of horizontal GPS coseismic displacement in the near-field has been assembled around the world in order to investigate a potential relationship between the displacement and the earthquake parameters. Regression analyses have been applied to the data of 120 interplate earthquakes having the magnitude (Mw 4.8-9.2). An empirical relationship for prediction near-field horizontal GPS coseismic displacement as a function of moment magnitude and the distance between hypocenter and near field GPS station has been established using the multi regression analysis. The obtained relationship allows assessing the coseismic displacements associated with some large historical earthquakes occurred along the Dead Sea fault system. Such a fair relationship could be useful for assessing the coseismic displacement at any point around the active faults.

scholarly journals Three Approaches to Interseismic Slip Rates on the Marmara Faults and Their Tensorial Correlations with the Kostrov-Based Strain Rates

2020 ◽  
Author(s):  
Volkan Özbey ◽  
Mehmet Sinan Özeren ◽  
Pierre Henry ◽  
Elliot Klein ◽  
Gerald Galgana ◽  
...  
Keyword(s):  
Reference Frames ◽  
Velocity Fields ◽  
Slip Distribution ◽  
Fault System ◽  
Marmara Sea ◽  
Strain Rates ◽  
Block Model ◽  
Slip Rates ◽  
Processing Strategies ◽  
Gps Velocities

&lt;p&gt;The interseismic slip distribution in the Marmara fault system represents both observational and modelling challenges. The observational challenge is obvious: the faults are under water and to understand their interseismic behavior (creeping versus locked) requires expensive and logistically difficult underwater geodetic measurements, alongside those on land. Up to now, two such underwater studies have been conducted and they suggest that the segment to the south of Istanbul zone (so-called Central segment) is locked while some creep is probably going on along the neighboring segment to the west. Given these two important findings, the slip distribution problem is still non-trivial due to the fact that our experiments so far demonstrate that the block-based slip inversions and those that only consider a single fault (with the same geometry as one of the boundaries of the blocks) give significantly different results. In this study we approach the problem using three methodologies: block models with spatially non-varying strains within individual blocks, a boundary element approach and a continuum kinematic approach. Although the block model does not give spatially varying strains, the inversion results from the block model can be used as an input to model strain field in the vicinity of the fault. We constract a formulation to correlate the results from these with the strain rates obtained using focal mechanism summations.&lt;/p&gt;&lt;p&gt;GPS velocities are taken from previous studies around the Marmara Sea such as Reilinger et al., (2006), Aktu&amp;#287; et al., (2009), Ergintav et al., (2014), &amp;#214;zdemir et al., (2016) and &amp;#214;zdemir and Karsl&amp;#305;o&amp;#287;lu, (2019). Since all studies have different processing strategies or by choosing different reference frames, the GPS velocity fields could not be combined directly. Hence, we combined all velocity fields by minimizing the residuals between the velocities of the common sites in the studies. For this purpose VELROT program (Herring et al 2015) was used. Reilinger et al., (2006) was selected the reference field and other velocity fields were aligned one by one on it. If the combined sigma of the pairs of velocity estimates in the residuals are greater than 2 mm yr&lt;sup&gt;-1&lt;/sup&gt;, that sites are excluded from the final velocity field. As a result, 127 GPS velocities were used in the developed models.&lt;/p&gt;

scholarly journals IDENTIFYING FAULT ACTIVITY IN THE CENTRAL EVOIKOS GULF (GREECE)

2018 ◽  
Vol 40 (1) ◽  
pp. 439 ◽  
Author(s):  
Th. Rondoyanni ◽  
D. Galanakis ◽  
Ch. Georgiou ◽  
I. Baskoutas
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Point Of View ◽  
Geological Mapping ◽  
Normal Faults ◽  
Geophysical Research ◽  
Alluvial Deposits ◽  
Moderate Seismicity ◽  
Limestone Bedrock ◽  
Topographic Relief

Geological mapping on a 1:5.000 scale and a tectonic analysis in the wider Chalkida region of the Island of Evia and the adjacent Drossia area of Central Greece, have allowed the identification of a number of active and potentially active normal faults. These faults have been formed or reactivated during the Late Quaternary, since they affect Pleistocene brackish and terrestrial deposits. Some of the faults affect the contact of the limestone bedrock with the Quaternary formations, presenting characteristic polished surfaces. The faults, in places covered by the alluvial deposits of the Chalkida plain, are also detected by geophysical research. Among the identified faults, the most important are considered the Aghios Minas- Chalkida, the Avlida and the Lefkadi active faults. The first one extends from Drossia to the Chalkida area, crossing the sea straights, and has an ENE-WSW direction and a south dip. The other two, are parallel antithetic faults oriented WNW-ESE, and bound the South Evoikos Gulf on the Greek mainland and the Evia Island respectively. The mapping and evaluation of active faults in this region of moderate seismicity, with low topographic relief and consequent absence of morphotectonic features, is especially important from a seismic hazard point of view.

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