Reply to “Comment on ‘Historical Seismicity of the Rijeka Region (Northwest External Dinarides, Croatia)—Part I: Earthquakes of 1750, 1838, and 1904 in the Bakar Epicentral Area’ by Davorka Herak, Ivica Sović, Ina Cecić, Mladen Živčić, Iva Dasović, and Marijan Herak” by Stathis C. Stiros

2017 ◽  
Vol 88 (6) ◽  
pp. 1537-1538
Author(s):  
Davorka Herak ◽  
Ivica Sović ◽  
Ina Cecić ◽  
Mladen Živčić ◽  
Iva Dasović ◽  
...  
2017 ◽  
Vol 88 (3) ◽  
pp. 904-915 ◽  
Author(s):  
Davorka Herak ◽  
Ivica Sović ◽  
Ina Cecić ◽  
Mladen Živčić ◽  
Iva Dasović ◽  
...  

2018 ◽  
Vol 89 (4) ◽  
pp. 1524-1536 ◽  
Author(s):  
Marijan Herak ◽  
Mladen Živčić ◽  
Ivica Sović ◽  
Ina Cecić ◽  
Iva Dasović ◽  
...  

2021 ◽  
Author(s):  
Tvrtko Korbar ◽  
Matija Vukovski ◽  
Snježana Markušić

<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>


2004 ◽  
Vol 20 (1_suppl) ◽  
pp. 39-52 ◽  
Author(s):  
Paolo Galli ◽  
Diego Molin

The eastern Molise earthquake had an epicentral intensity of Io=7–8 MCS (Mercalli-Cancani-Sieberg scale) and a maximum intensity of Imax=8–9 in the village of San Giuliano di Puglia. The historical portion of this village, built on a marly limestone hill, had intensities of 6–7 MCS, whereas the most recently developed area, on a crest of marly clays, had a local intensity of I=9–10 MCS, and was almost totally destroyed. Neighboring villages were generally struck with an intensity of 6–7 MCS. In several places, the damage was due to gravity-driven phenomena affecting both the rocky and clayey substratum of the villages. The epicentral area is characterized by the lack of historical earthquakes comparable to the 2002 sequence, having suffered only the effects of distant, strong (M>6.5) events, coming either from the Apennine seismogenic belt or from the Gargano area.


1994 ◽  
Vol 65 (2) ◽  
pp. 167-171 ◽  
Author(s):  
L.T. Long ◽  
A. Kocaoglu ◽  
R. Hawman ◽  
P.J.W. Gore

Abstract During the summer of 1993, the residents in the Norris Lake community, Lithonia, Georgia, were bothered by an incessant swarm of earthquakes. The largest, a magnitude 2.7 on September 23, showed a normal aftershock decay and occurred after the main swarm. Over 10,000 earthquakes have been detected, of which perhaps 500 were felt. The earthquakes began June 8, 1993, with a 5-day swarm. The residents, accustomed to quarry explosions, suspected the quarries of irregular activities. To locate the source of the events, a visual recorder and a digital event recorder were placed in the epicentral area. Ten to 20 events were detected per day for the next three weeks. The swarm then escalated to a peak of over 100 per day by August 15, 1993. Activity following the peak died down to about 10 events per day. The magnitude 2.7 event of September 23 was followed by a normal aftershock sequence. The larger events were felt with intensity V within 2 km of their epicenter, and noticed (intensity II) to a distance of 15 km. Some incidents of cracked wallboard and foundations have been reported, but no significant damage has been documented. Preliminary locations, based on data from digital event recorders, suggest an average depth of 1.0 km. The hypocenters are in the Lithonia gneiss, a massive migmatite resistant to weathering and used locally as a building stone. The epicenters are 1 to 2 km south-southwest of the Norris Lake Community. The cause of the seismicity is not yet known. The earthquakes are characteristic of reservoir-induced earthquakes; however, Norris Lake is a small (96 acres), 2 to 5m deep recreational lake which has existed since the 1950s.


2021 ◽  
Vol 14 (11) ◽  
Author(s):  
Abdelhakim Ayadi ◽  
Farida Ousadou ◽  
Kahina Roumane ◽  
Assia Harbi ◽  
Said Maouche ◽  
...  

Author(s):  
D Spallarossa ◽  
M Cattaneo ◽  
D Scafidi ◽  
M Michele ◽  
L Chiaraluce ◽  
...  

Summary The 2016–17 central Italy earthquake sequence began with the first mainshock near the town of Amatrice on August 24 (MW 6.0), and was followed by two subsequent large events near Visso on October 26 (MW 5.9) and Norcia on October 30 (MW 6.5), plus a cluster of 4 events with MW > 5.0 within few hours on January 18, 2017. The affected area had been monitored before the sequence started by the permanent Italian National Seismic Network (RSNC), and was enhanced during the sequence by temporary stations deployed by the National Institute of Geophysics and Volcanology and the British Geological Survey. By the middle of September, there was a dense network of 155 stations, with a mean separation in the epicentral area of 6–10 km, comparable to the most likely earthquake depth range in the region. This network configuration was kept stable for an entire year, producing 2.5 TB of continuous waveform recordings. Here we describe how this data was used to develop a large and comprehensive earthquake catalogue using the Complete Automatic Seismic Processor (CASP) procedure. This procedure detected more than 450,000 events in the year following the first mainshock, and determined their phase arrival times through an advanced picker engine (RSNI-Picker2), producing a set of about 7 million P- and 10 million S-wave arrival times. These were then used to locate the events using a non-linear location (NLL) algorithm, a 1D velocity model calibrated for the area, and station corrections and then to compute their local magnitudes (ML). The procedure was validated by comparison of the derived data for phase picks and earthquake parameters with a handpicked reference catalogue (hereinafter referred to as ‘RefCat’). The automated procedure takes less than 12 hours on an Intel Core-i7 workstation to analyse the primary waveform data and to detect and locate 3000 events on the most seismically active day of the sequence. This proves the concept that the CASP algorithm can provide effectively real-time data for input into daily operational earthquake forecasts, The results show that there have been significant improvements compared to RefCat obtained in the same period using manual phase picks. The number of detected and located events is higher (from 84,401 to 450,000), the magnitude of completeness is lower (from ML 1.4 to 0.6), and also the number of phase picks is greater with an average number of 72 picked arrival for a ML = 1.4 compared with 30 phases for RefCat using manual phase picking. These propagate into formal uncertainties of ± 0.9km in epicentral location and ± 1.5km in depth for the enhanced catalogue for the vast majority of the events. Together, these provide a significant improvement in the resolution of fine structures such as local planar structures and clusters, in particular the identification of shallow events occurring in parts of the crust previously thought to be inactive. The lower completeness magnitude provides a rich data set for development and testing of analysis techniques of seismic sequences evolution, including real-time, operational monitoring of b-value, time-dependent hazard evaluation and aftershock forecasting.


2021 ◽  
Vol 107 ◽  
pp. 103121
Author(s):  
Andrés Núñez Meneses ◽  
Pierre Lacan ◽  
F. Ramón Zúñiga ◽  
Laurence Audin ◽  
María Ortuño ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emanuele Tondi ◽  
Anna Maria Blumetti ◽  
Mišo Čičak ◽  
Pio Di Manna ◽  
Paolo Galli ◽  
...  

AbstractWe provide here a first-hand description of the coseismic surface effects caused by the Mw 6.4 Petrinja earthquake that hit central Croatia on 29 December 2020. This was one of the strongest seismic events that occurred in Croatia in the last two centuries. Field surveys in the epicentral area allowed us to observe and map primary coseismic effects, including geometry and kinematics of surface faulting, as well as secondary effects, such as liquefaction, sinkholes and landslides. The resulting dataset consists of homogeneous georeferenced records identifying 222 observation points, each of which contains a minimum of 5 to a maximum of 14 numeric and string fields of relevant information. The earthquake caused surface faulting defining a typical ‘conjugate’ fault pattern characterized by Y and X shears, tension cracks (T fractures), and compression structures (P shears) within a ca. 10 km wide (across strike), NW–SE striking right-lateral strike-slip shear zone (i.e., the Petrinja Fault Zone, PFZ). We believe that the results of the field survey provide fundamental information to improve the interpretation of seismological, GPS and InSAR data of this earthquake. Moreover, the data related to the surface faulting may impact future studies focused on earthquake processes in active strike-slip settings, integrating the estimates of slip amount and distribution in assessing the hazard associated with capable transcurrent faults.


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