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 ESTIMATION OF SUBSURFACE STRUCTURE BASED ON MICROTREMOR, BORE HOLE OBSERVATIONS AND STOCHASTIC STRONG GROUND MOTION SIMULATIONS IN PALU CITY, CENTRAL SULAWESI, INDONESIA: A VALIDATION AND SENSITIVITY STUDY ON THE 23 JANUARY 2005 (PALU) EARTHQUAKE

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Pyi Soe Thein ◽  
Subagyo Pramumijoyo ◽  
Wahyu Wilopo ◽  
Agung Setianto ◽  
Kirbani Sri Brotopuspito ◽  
...  
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Soil Condition ◽  
Fault System ◽  
Earthquake Ground Motion ◽  
Subsurface Structure ◽  
Ground Acceleration ◽  
Central Sulawesi ◽  
Strong Ground

In this study, we investigated the subsurface structure and strong ground motion parameters for Palu City. One of the major structures in Central Sulawesi is the Palu-Koro Fault system. Several powerful earthquakes have struck along the Palu-Koro Fault during recent years, one of the largest of which was an M 6.3 event that occurred on January 23, 2005 and caused several casualties. Following the event, we conducted a microtremor survey to estimate the shaking intensity distribution during the earthquake. From this survey we produced a map of the peak ground acceleration, velocity and ground shear strain in Palu City. We performed single observations of microtremors at 151 sites in Palu City. The results enabled us to estimate the site-dependent shaking characteristics of earthquake ground motion. We also conducted 8-site microtremor array investigation to gain a representative determination of the soil condition of subsurface structures in Palu. From the dispersion curve of array observations, the central business district of Palu corresponds to relatively soil condition with Vs ≤ 300 m/s, the predominant periods due to horizontal vertical ratios (HVSRs) are in the range of 0.4 to 1.8 s and the resonant frequency are in the range of 0.7 to 3.3 Hz. Three boreholes were throughout the basin especially in Palu area to evaluate the geotechnical properties of subsurface soil layers. The depths are varying from 1 m to 30 m. Strong ground motions of the Palu area were predicted based on the empirical stochastic green’s function method. Peak ground acceleration and peak ground velocity becomes more than 0.04 g and 30 kine in some areas, which causes severe damage for buildings in high probability. Keywords: Palu-Koro fault, microtremor, bore holes, peak ground acceleration and velocity.

Evaluation of Peak Ground Acceleration and Response Spectra Considering the Local Site Effects

2010 ◽  
Vol 1 (1) ◽  
pp. 25-41 ◽  
Author(s):  
T. G. Sitharam ◽  
K. S. Vipin
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Site Effects ◽  
Response Spectra ◽  
Probabilistic Logic ◽  
Site Classification ◽  
Ground Acceleration ◽  
Entire Study ◽  
Local Site Effects ◽  
Local Site

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluated for the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work.

scholarly journals Seismic hazard assessment and local site effect evaluation in Hanoi, Vietnam

2017 ◽  
Vol 17 (4B) ◽  
pp. 82-95
Author(s):  
Nguyen Anh Duong ◽  
Pham Dinh Nguyen ◽  
Vu Minh Tuan ◽  
Bui Van Duan ◽  
Nguyen Thuy Linh
Keyword(s):  
Seismic Hazard ◽  
Shear Wave ◽  
Ground Motion ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Peak Ground Acceleration ◽  
Site Effect ◽  
Local Site Effect ◽  
Ground Acceleration ◽  
Local Site

In this study, we have carried out the probabilistic seismic hazard analysis in Hanoi based on the latest seismotectonic data. The seismic hazard map shows peak ground acceleration values on rock corresponding to the 10% probability of exceedance in a 50-year time period (approximately return periods of 500 years). The calculated results reveal that the maximum ground acceleration can occur on rock in Hanoi is about 0.13 g corresponding to the shaking intensity level of VIII on the MSK-64 scale. The ground motion values calculated on rock vary according to the local site conditions. We have evaluated and corrected the local site effects on ground motion in Ha Dong district, Hanoi by using microtremor and borehole data. The Nakamura’s H/V spectral ratio method has been applied to establish a map of ground dominant periods in Ha Dong with a TS range of 0.6 - 1.2 seconds. The relatively high values of periods indicate that Ha Dong has soft soil and thick Quaternary sediments. The sediment thickness in Ha Dong is calculated to vary between 30 - 75 m based on ground dominant periods and shear wave velocity VS30 = 171 - 254 m/s. The results of local site effect on ground motion show that the 500-year return period peak ground acceleration in Ha Dong ranges from 0.13 g to 0.17 g. It is once again asserted that the seismic hazard in Hanoi is a matter of great concern, due not only to the relatively high ground acceleration, but also to the seismic characteristics of soil (low shear wave velocity, ground dominant period of approximately 1 second).

The epicentral fingerprint of earthquakes

2021 ◽  
Author(s):  
Patrizio Petricca ◽  
Christian Bignami ◽  
Carlo Doglioni
Keyword(s):  
Seismic Waves ◽  
Hanging Wall ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Coseismic Deformation ◽  
Far Field ◽  
Ground Acceleration ◽  
Epicentral Area ◽  
Local Site ◽  
Field Area

<p>InSAR images allow to detect the coseismic deformation, delimiting the epicentral area where the larger displacement has been concentrated. The main observations are: 1) the most deformed area in the ideal case is elliptical (for dip-slip faults) or quadrilobated (for strike-slip faults) and coincides with the surface projection of the volume coseismically mobilized in the hanging wall of thrusts and normal faults, or the crustal walls adjacent to strike-slip faults; 2) the dimension of the deformed area detected by InSAR scales with magnitude of earthquake and for M≥6 is always larger than 100 km, increasing to more than 550 km<sup>2</sup> for M≈6.5; 3) the seismic epicenter rarely coincide with the area of larger vertical shaking (either downward or upward); 4) the higher macroseismic intensity corresponds to the area of larger vertical displacement, apart from local site amplification effects; 5) outside this area, the vertical displacement is drastically lower, determining the strong attenuation of seismic waves and the decrease of the peak ground acceleration in the surrounding far field area, apart from local site amplifications; 6) the segment of the activated fault constrains the area where the vertical oscillations have been larger, allowing the contemporaneous maximum freedom degree of the crustal volume affected by horizontal maximum shaking, i.e., the near field or epicentral area; 7) therefore, the epicentral area and volume are active, i.e., they coseismically move and are contemporaneously crossed by seismic waves (active volume), whereas the surrounding far field area is mainly fixed and passively crossed by seismic waves (passive volume). Therefore, here we show how the InSAR images of areas affected by earthquakes represent the fingerprint of the epicentral area where the largest shaking has taken place during an earthquake. Seismic hazard assessments should rely on those data.</p>

Attenuation of earthquake ground motion in Japan including deep focus events

1995 ◽  
Vol 85 (5) ◽  
pp. 1343-1358
Author(s):  
Gilbert L. Molas ◽  
Fumio Yamazaki
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Soil Classification ◽  
Peak Ground Velocity ◽  
Earthquake Ground Motion ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Distance Dependence ◽  
Recording Station ◽  
Deep Focus

Abstract New attenuation equations for peak ground acceleration and velocity for Japan are developed. The equations are derived using extensive data recorded by the new JMA-87-type accelerometers, which do not require instrumental corrections that the older SMAC-type accelerometers do. Earthquakes with depths up to 200 km are used to make the equation applicable to subduction zone regions, which are common in Japan. Effects of depth and local site on the attenuation are considered simultaneously with the distance dependence and magnitude dependence using a two-stage regression procedure to separate the magnitude dependence from the distance dependence. Since the resulting normal equations become singular, an iterative partial regression algorithm is proposed. It is found that for the same magnitude and distance, peak ground motion increases as depth increases. The variation of the station coefficients with respect to the corresponding soil-type classification is quite wide. The station coefficients for the peak ground acceleration are found to be weakly correlated with the general soil classification, while a stronger correlation was found for the peak ground velocity. The resulting attenuation relations are given by log10PGA=0.206+0.477MJ−log10r−0.00144r−0.00144r+0.00311h+cia,log10PGV=−1.769+0.628MJ−log10r−0.00130r−0.00144r+0.00222h+civ, where PGA (cm/sec2) and PGV (cm/sec) are the larger of the peak accelerations and velocities from two horizontal components, MJ is the JMA magnitude, r is the closest distance to the fault rupture, h is the depth, and ci is the station coefficient of the recording station. The mean of the coefficients of the JMA stations is given by ci = 0.

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>

Evaluation of Peak Ground Acceleration and Response Spectra Considering the Local Site Effects

2012 ◽  
pp. 1-17
Author(s):  
Sitharam T. G. ◽  
Vipin K. S.
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Site Effects ◽  
Response Spectrum ◽  
Response Spectra ◽  
Site Classification ◽  
Ground Acceleration ◽  
Local Site Effects ◽  
Local Site ◽  
Uniform Hazard Response Spectrum

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluated for the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work.

Effect of Ridge Topography on Earthquake Ground Motion

2012 ◽  
Vol 594-597 ◽  
pp. 1696-1701
Author(s):  
Guo Dong Xu ◽  
Zheng Hua Zhou ◽  
Jing Shan Bo ◽  
Wei Hua Fang
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Response Spectrum ◽  
Vertical Direction ◽  
Earthquake Ground Motion ◽  
Topographic Effect ◽  
Ground Acceleration ◽  
Seismic Ground Motion ◽  
Remarkable Effect ◽  
Motion Amplitude

The ridge topography can substantially influence seismic ground motion and, in general, causes the amplification of seismic ground motion amplitude at ridges. Fortunately, sets of three-component accelerogram, obtained by the observation arrays for topographic effect at Zigong Xishan, Jiangyou Doutuan and Qingchuan Sanguo from the great Wenchuan earthquake and its aftershocks, provided basic data for analyzing the effect of ridge topography on seismic ground motion. On the base of these acceleration records, peak ground acceleration and response spectrum ratios are calculated, and examined and compared in order to grasp the effect of ridge topography on ground motion. The findings showed that ridge topography has the remarkable effect on seismic ground motion, in which the amplification characteristics varies depending on the shape of ridge topography, and the amplification effect of the horizontal directions are not similar to the vertical direction, and in some periods are even less than 1.0.

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