KARAGANDA (KARABASS) EARTHQUAKE onJune 21, 2014, KP=11.7, MS=4.0, I0р=5 (Central Kazakhstan)

The work shows the results of macroseismic analysis of the earthquake with mb=5.2 occurred near Karaganda on June 21, 2014 and recorded by seismic stations of the Institute of Geophysical Research ME RK. Basing on the data of macroseismic examination that included acquisition and analysis of information on the dam-aged houses and industrial buildings, the shaking intensity on MSK-64 scale was estimated for 34 settlements on the territory of ≈100 km radius around the earthquake epicenter. For the Karaganda earthquake localized in the area that was previously considered aseismic the basic parameters is studied, the focal mechanism is constructed, and the isoseismal map is compiled. Basing on the analysis of seismic records, focal mechanism and geological and tectonic features of the region, it was concluded that the natural-induced nature of the earthquake is most probable.

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Crustal structure of the Barents Sea from 3D active seismic tomography.

10.5194/egusphere-egu2020-11649 ◽

2020 ◽

Author(s):

Alexey Shulgin ◽

Jan Erik Lie ◽

Espen Harris Nilsen ◽

Jan Inge Faleide ◽

Sverre Planke

Keyword(s):

Crustal Structure ◽

Seismic Tomography ◽

Barents Sea ◽

Seismic Exploration ◽

Seismic Profiles ◽

Seismic Stations ◽

S Waves ◽

The Barents Sea ◽

Seismic Records ◽

Structural Architecture

The Barents Sea shelf has been covered by numerous wide-angle seismic profiles aiming to resolve the crustal structure of the shelf. However, the overall structural architecture of the crystalline crust is still not fully understood, due to limited and sparse distribution of deep-sampling seismic profiles.&#160;The petroleum related seismic exploration in Norwegian waters has been ongoing for decades. The recent increase of the seismic broadband stations onshore (including temporal deployments) provokes the idea to use these stations and the active seismic sources from the regional seismic reflection surveys, including academic and industry seismic projects, to reveal the crustal-scale structure of the western Barents Sea.We have analyzed seismic records from 8 permanent seismic stations from Norway, Sweden and Finland, and 12 temporally deployed broadband seismic stations from the ScanArray seismic network, which recorded more than 100&#8217;000 marine airgun shots from academic and oil industry campaigns in the south-western quarter of the Barents Sea.The overall quality of the seismic records is exceptionally good. We observe clear phases recorded from offsets reaching 750 km. The identified phases include refracted crustal and mantle arrivals as well as Moho reflections, including both P and S waves. The overall quantity, quality, and the geometry of the seismic data makes it perfect for the application of the 3D joint refraction/reflection travel time seismic tomography to study the crustal structure of the Barents Sea. In this work we would like to present our first results from the 3D seismic tomography.

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Earthquake on December 12, 2020 in the Anapa zone with Mw=3.8, I0=4-5

Российский сейсмологический журнал [Russian Journal of Seismology] ◽

10.35540/2686-7907.2021.2.03 ◽

2021 ◽

Vol 3 (2) ◽

pp. 52-66

Author(s):

Anastasia Zvereva ◽

Andrei Klianchin ◽

Irina Gabsatarova

Keyword(s):

Focal Mechanism ◽

Seismic Survey ◽

Corner Frequency ◽

Shelf Zone ◽

Density Level ◽

Macroseismic Data ◽

North Caucasus ◽

Spectral Parameters ◽

Seismic Stations ◽

The North

The article presents instrumental and macroseismic data on the earthquake on 12.12.2020 at 14:54 with Mw=3.8, h=30 km. The epicenter and parameters of the earthquake were deter-mined using instrumental data from the network of regional seismic stations in the western zone of the North Caucasus of the EGS RAS. This earthquake occurred in the shelf zone of the Eastern Black Sea coast near the resort town of Anapa, in the Anapa seismically active area. This area tectonically is the conjunction of the northern side of the Tuapse trough and the thrust front of the Greater Caucasus. The focal mechanism for the earthquake was calcu-lated. The solution of the focal mechanism was obtained from the polarization in P-waves at 29 seismic stations. From the focal follows the type of source up thrust-thrust movement. The GS RAS organized a macroseismic survey in the Anapa and Novorossiysk regions on the “VKontakte” social network a day after the earthquake. According to the results of the study, 144 respondents in 15 settlements in 7 days were interviewing. The maximum observed in-tensity was I=4-5 points in Su-Psekh and Varvarovka according to the results of the macro-seismic survey, a map of the distribution of intensity points was create. The SEISAN software package calculated the spectral parameters of the source: seismic moment, corner frequency, spectral density level and spectral magnitude Mw.

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Initial motion of the first longitudinal earthquake wave recorded at Pasadena and Huancayo*

Bulletin of the Seismological Society of America ◽

10.1785/bssa0420020175 ◽

1952 ◽

Vol 42 (2) ◽

pp. 175-195

Author(s):

Markus Båth

Keyword(s):

The Other ◽

Geological Time ◽

P Waves ◽

Seismic Stations ◽

Transition Zones ◽

The World ◽

Seismic Records ◽

First Motion ◽

Boundary Lines ◽

Initial Motion

Summary and Outlook This study is concerned with the initial motion of the P waves at Pasadena and Huancayo. The results have been given in maps. In order to make the distribution more obvious, some boundary lines have been drawn. These boundaries are generally not to be taken as geometrical lines, but rather as transition zones. The appearance and positions of these lines can clearly be given in more or less detail, depending on the number of earthquakes used. For an earthquake well within an area of either compression or dilatation we can expect a clear first motion of P, whereas for earthquakes within mixed areas and for earthquakes on or in the vicinity of boundary lines we generally cannot. As a general conclusion, we find that compressions and dilatations have certain definite geographical distributions, indicating that the general tectonics are the same within relatively large areas. Furthermore, these distributions are independent of time, throughout the period for which seismic records are available, and presumably the distributions change only with geological time. The distributions we have obtained in particular for Pasadena and Huancayo are also to be taken as reliable results. On the other hand, it should be strongly emphasized that the efforts made to explain some of the observed distributions in terms of tectonics are highly tentative. In order to arrive at more definite results regarding the general tectonics of the earthquake regions, we need the detailed distributions of compression and dilatation for a large number of stations. The author would like to use this opportunity to suggest strongly that these distributions be determined for the seismic stations over the world. In such work we have to bear in mind that only cases which are certain beyond doubt should be used. Naturally, the notations “compression” and “dilation” refer to the motion of the ground and not to the motion of the seismmograph pendulum. When such distributions have been determined for a large number of stations, they could be brought together to give more definite information. I should also like to suggest that the initial motion of P waves should be given in seismic bulletins whenever it can be determined with reliability, but only then. Directions determined only from records of horizontal seismographs may naturally be used also, once the location of the epicenter is known approximately.

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Analysis of M 5.3 Sumbawa, Indonesia earthquake 2020 and its aftershocks based on hypocenter relocation from BMKG seismic stations

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/873/1/012070 ◽

2021 ◽

Vol 873 (1) ◽

pp. 012070

Author(s):

M Ramdhan ◽

Priyobudi ◽

A Mursityanto ◽

K H Palgunadi ◽

Daryono

Keyword(s):

Focal Mechanism ◽

Difference Method ◽

Fault Plane ◽

Active Faults ◽

Disaster Mitigation ◽

Double Difference ◽

Seismic Stations ◽

Hypocenter Relocation ◽

Splay Faults ◽

Moderate Magnitude

Abstract The 2020 Sumbawa earthquake of moderate magnitude (M 5.3) produced very significant aftershocks. Based on the computation of Utsu’s method, those aftershocks would be ended after the 20th day. Those earthquakes along 20 days were relocated using double-difference method. The relocation results show the southwest-northeast orientation and getting deeper into the northwest direction. Those two directions show the strike and the dip from the fault plane of the earthquake which was consistent with the focal mechanism released by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). Those results showed the majority of earthquakes occurred at a depth of shallower than 20 km. Those earthquake depths were fit with the previous study showing the crustal thickness beneath Sumbawa Island that was about 28 km. We also found that those earthquakes occurred at splay faults propagating to decollement structure. This study is beneficial for earthquake disaster mitigation especially in updating active faults on Sumbawa Island.

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Study of the Montenegro earthquake sequence (March-July 1979)

Bulletin of the Seismological Society of America ◽

10.1785/bssa0710041233 ◽

1981 ◽

Vol 71 (4) ◽

pp. 1233-1248

Author(s):

R. Console ◽

P. Favali

Keyword(s):

Focal Mechanism ◽

Main Shock ◽

Border Region ◽

Earthquake Sequence ◽

Space Distribution ◽

Previous Knowledge ◽

Seismic Stations ◽

Coast Line ◽

Time Space ◽

Adriatic Coast

abstract Data from more than 80 European seismic stations, concerning foreshocks, the main shock, and aftershocks of the earthquake which occurred near the coast of Montenegro on 15 April 1979, have been collected and analyzed. The data have allowed the focal mechanism of the two strongest shocks to be estimated. The hypocentral coordinates of more than 180 aftershocks and some foreshocks have been also computed, giving the time-space distribution of the sequence. The shocks are mostly contained in an area about 100 km long and 30 km wide, almost corresponding to the Adriatic coast line of the Yugoslavia-Albania border region. The hypocentral depths, although determined approximately, appear to be in the order of 15 to 20 km. The results have been compared with previous knowledge of the tectonics of the zone.

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Analysis of the Donggala-Palu Tsunami Characteristics based on Rupture Duration (Tdur) and Active Fault Orientation using the HC-plot Method

Jurnal Geofisika ◽

10.36435/jgf.v17i1.392 ◽

2019 ◽

Vol 17 (1) ◽

pp. 16

Author(s):

Ramadhan Priadi ◽

Angga Wijaya ◽

Maria Annaluna Pasaribu ◽

Riska Yulinda

Keyword(s):

Focal Mechanism ◽

Vertical Component ◽

Earthquake Source ◽

P Wave ◽

Nodal Plane ◽

Waveform Data ◽

Seismic Stations ◽

The North ◽

Rupture Duration ◽

Direction Field

September 28th, 2018, Donggala-Palu earthquake M 7.5 occurred at depth of 12 km and generated tsunami to be released off the coast in Palu Bay. The tsunami that occurred in Palu was very interesting because the results of the earthquake source mechanism Palu had a type of strike-slip fault that should not have generated a tsunami. This study purpose to estimate the characteristics of the Donggala-Palu tsunami based on rupture duration ( and orientation fault activated using the HC-plot method. The data used in this study are data waveforms from 17 seismic stations and CMT Global catalog data with the area of research 0.87 0 N-1.78 0S dan 118.640E- 120.95 0E. The waveform data used is a phase P-PP vertical component signal with a Bandpass-filter 1-5 Hz for determination . The fastest rupture duration from the earthquake source is obtained from the calculation of each station. Delay time measurement after P wave for 90% (T0.9), 80% (T0.8), 50% (T0.5), dan 20% (T0.2) from its peak value. Then the HC-plot method is used to estimate the orientation of generator fault Palu earthquake and the direction of rupture from the focal mechanism. From the results of processing obtained 2 pairs of seismic stations with almost the same distance but with different azimuths. The fastest rupture duration is at BBSI station with value of 82.014 s and distance from station to epicenter . So that the rupture direction is in the azimuth from the north. The result of fault orientation was obtained hypocenter distance to the centroid for nodal plane 1 is 6.32 km and nodal plane 2 is 30.17 km with distance centroid to hypocenter is 31.22 km. So in Palu earthquake, the tsunami generator fault was in nodal plane 1 with direction north-south. Criteria obtained indicate that the Palu earthquake M 7.5 has potential for a tsunami because of its value has meet ≥ 65 s, but from the result of the focal mechanism direction field not passing through the Palu bay is thought to be another parameter that generates a tsunami and Palu koro fault line uncharted.

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GEODYNAMICS

GEODYNAMICS ◽

10.23939/jgd2011.02.035 ◽

2011 ◽

Vol 2(11)2011 (2(11)) ◽

pp. 35-37

Author(s):

S. T. Verbytskyi ◽

◽

Yu. T. Verbytskyi ◽

Keyword(s):

Short History ◽

Seismic Stations ◽

Carpathian Region ◽

History Of ◽

Basic Parameters

Shows the short history of seismological observations in the Carpathian region, the necessity of improving the seismic equipment and automation of processing the data. Is the list of existing seismic stations, their equipment and basic parameters layout. Given a list of problems to be solved by using materials obtained seismological observations. Shows the main directions of modernization of the hardware receive seismic information, communications and software.

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INDIKASI KETERDAPATAN ENDAPAN PLASER PEMBAWA TIMAH DAN UNSUR TANAH JARANG (REE), DI PERAIRAN TODAK, SINGKEP, KEPULAUAN RIAU

JURNAL GEOLOGI KELAUTAN ◽

10.32693/jgk.13.2.2015.266 ◽

2016 ◽

Vol 13 (2) ◽

pp. 109

Author(s):

Udaya Kamiludin ◽

I Nyoman Astawa ◽

Moch. Akrom Mustafa

Keyword(s):

Rare Earth ◽

Seismic Data ◽

Earth Element ◽

Single Channel ◽

Placer Deposit ◽

Surrounding Area ◽

Geophysical Research ◽

Seismic Sequences ◽

Seismic Records ◽

Riau Archipelago

Penelitian geofisika di Perairan Todak, Singkep, Kepulauan Riau menggunakan seperangkat peralatan seismik pantul dangkal saluran tunggal. Tujuan penelitian ini adalah untuk menunjang penelitian keterdapatan endapan plaser pembawa timah dan unsur tanah jarang (REE). Hasil interpretasi rekaman seismik diperoleh terdapatnya lembah/mangkuk yang terbentuk secara alami akibat adanya terobosan batuan granit, di mana lembah/mangkuk-mangkuk ini merupakan tempat terjadinya sedimentasi dari hasil pelapukan batuan di sekitarnya. Hasil interpretasi rekaman seismik pantul saluran tunggal analog di perairan Todak, Singkep, dapat diklasifikasikan menjadi 3 runtunan yaitu runtunan A, B, dan runtunan C.Kata kunci Data seismik, endapan plaser, lembah/mangkuk, Perairan Todak. Geophysical research at Todak, Singkep, Riau Archipelago Province, by using single channel sahllow seismic refletion. The purpose of research is to support placer deposit bearing tin and rare earth element research at this area. From seismic interpretation can be recognized the distribution of valley/bowls which is naturally formed, caused by granite rock intrusion. Those valleys are sedimentation places of wheathered rock from the surrounding area. Beside that, the seismic research also for determining the placer deposit thickness. Interpratation of analog single channel seismic records in the Todak waters, Singkep, result 3 seismic sequences and intrusive feature, A sequences, B, and C. Keywords: Seismic data, placer deposit, valley/basin, Todak Watres.

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COVID-19 lockdown effects on the seismic recordings in Central America

Solid Earth ◽

10.5194/se-12-2127-2021 ◽

2021 ◽

Vol 12 (10) ◽

pp. 2127-2144

Author(s):

Mario Arroyo-Solórzano ◽

Diego Castro-Rojas ◽

Frédérick Massin ◽

Lepolt Linkimer ◽

Ivonne Arroyo ◽

...

Keyword(s):

Costa Rica ◽

El Salvador ◽

Central America ◽

Seismic Noise ◽

Temporal Variations ◽

Noise Levels ◽

Contributing Factors ◽

Seismic Stations ◽

Before And After ◽

Seismic Records

Abstract. A noticeable decrease in seismic noise was registered worldwide during the lockdown measures implemented in 2020 to prevent the spread of COVID-19. In Central America, strong lockdown measures started during March of 2020. In this study, we used seismic stations from Costa Rica, Guatemala, El Salvador, and Nicaragua to study the effects of these measures on seismic records by characterizing temporal variations in the high-frequency band (4–14 Hz) via spectral and amplitude analyses. In addition, we studied the link between the reduction in seismic noise and the number of earthquake detections and felt reports in Costa Rica and Guatemala. We found that seismic stations near the capitals of Costa Rica, Guatemala, and El Salvador presented a decrease in their typical seismic noise levels, from 200 to 140, from 100 to 80, and from 120 to 80 nm, respectively. Our results showed that the largest reduction of ∼ 50 % in seismic noise was observed at seismic stations near main airports, busy roads, and densely populated cities. In Nicaragua, the seismic noise levels remained constant (∼ 40 nm), as no lockdown measures were applied. We suggest that the decrease in seismic noise levels may have increased earthquake detections and the number of felt reports of low-magnitude earthquakes. However, the variations observed in several seismic parameters before and after the lockdown are not significant enough to easily link our observations or separate them from other contributing factors. Our results imply that the study of seismic noise levels can be useful to verify compliance with lockdown measures and to explore their effects on earthquake detection and felt reports.

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Earthquake source parameter analysis shows hydraulic fracturing induced events are consistent with fault reactivation under regional stress in northeastern British Columbia, Canada

10.5194/egusphere-egu2020-8240 ◽

2020 ◽

Author(s):

Marco Pascal Roth ◽

Alessandro Verdecchia ◽

Kilian B. Kemna ◽

John Onwuemeka ◽

Rebecca M. Harrington ◽

...

Keyword(s):

British Columbia ◽

Hydraulic Fracturing ◽

Focal Mechanism ◽

Seismic Moment ◽

Parameter Analysis ◽

Active Time ◽

Regional Stress ◽

Seismic Stations ◽

Stress Orientation ◽

Time Periods

An increasing number of M3+ earthquakes have been associated with Hydraulic Fracturing (HF) injection activity in low-permeable tight shale formations in the Western Canada Sedimentary Basin (WCSB) in the last decade. These include a Mw 4.6 on 08/17/2015 near Ft. St. John, a ML 4.5 on 11/30/2018, and two ML 3.2 on 10/05/2019, 10/08/2019 near Dawson Creek, British Columbia. Increased seismic activity in the Dawson-Septimus area prompted a temporary deployment of seismic stations in a joint effort between McGill University and the Ruhr University Bochum in order to perform higher-resolution monitoring relative to the regional seismic station coverage. Here, we use waveform data from that deployment of 22 (dominantly broadband) stations in close proximity to numerous HF wells in an area of roughly 60 x 70 km2, between July 2017 and August 2019, as well as records from 6 additional seismic stations northwest of the study area. In total, we detect 6222 local earthquakes, of which 5325 surpass a quality control criterion of having a horizontal location error &#8804; 3 km. An investigation of the spatial and temporal correlation between injection and earthquake initiation using a cross-correlation based event similarity analysis during seismically active time periods reveals a high degree of event similarity within various clusters and a strong correlation with individual injection episodes at specific HF wells. In addition, event clusters also exhibit similar patterns in daily cumulative seismic moment, independent of differences in waveform characteristics.As individual clusters may represent the activation of specific geological structures, we perform double-difference relative relocation of seismicity to identify fault orientations. In addition, we invert for focal mechanism solutions per event cluster to check consistency with structures inferred with relocated hypocenters, and perform spectral fitting for source parameter analysis. Event relocations are performed on individual families, where the total catalog is divided into subsets corresponding to 24 seismic active time periods where 43 event families are active. Relocating each earthquake family separately allows us to successfully relocate 4571 out of the total 5325 events. The relative relocations align in two dominant orientations, with one roughly perpendicular to the maximum horizontal regional stress orientation, and the other at low angles to the maximum regional stress orientation on a regional scale around individual HF wells. Focal mechanism estimates for events with M > 2.0 result in two primary groups of faulting mechanisms: strike-slip deformation on faults implied by lineations striking at low angles to SH, and thrust-faulting deformation on faults implied by lineations perpendicular to SH. Seismic moment and corner frequency estimates from single spectrum and spectral ratio fitting as well as scaling relations will be presented.

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