scholarly journals Okhotsk deep earthquake 24.05.2013: nature of coseismal earth’s oscillations and estimation of P-wave amplitudes at teleseismic distances

2019 ◽  
Vol 486 (2) ◽  
pp. 237-242
Author(s):  
I. P. Kuzin ◽  
L. I. Lobkovskiy ◽  
K. A. Dozorova
Keyword(s):  
Sea Of Okhotsk ◽  
Seismic Waves ◽  
P Wave ◽  
P Waves ◽  
Deep Earthquake ◽  
Epicentral Area ◽  
Seismic Stations ◽  
The Sea Of Okhotsk ◽  
Gps Observations

The results of coseismic GPS observations in the epicentral area of 2013 Sea-of- Okhotsk earthquake are presented and specific features of seismic waves amplitudes variations with distance are detected basing on the records of Russian and international seismic stations. Global propagation of P-waves for the Sea-of-Okhotsk and Bolivian (09.06.1994) earthquakes was studied and their amplitudes on teleseismic distances were estimated.

scholarly journals Estimation of Geodynamic Properties using Seismic Techniques at a Steel Rolling Factory, Northwestern Gulf of Suez, Egypt

2020 ◽  
Vol 8 (6) ◽  
pp. 1785-1794
Keyword(s):  
Wave Velocity ◽  
Seismic Waves ◽  
Seismic Refraction ◽  
Industrial Area ◽  
P Wave ◽  
Gulf Of Suez ◽  
S Wave ◽  
P Waves ◽  
Steel Rolling ◽  
P Wave Velocity

The objective of the current investigations is to estimate the dynamic geotechnical properties necessary for evaluating the conditions of the subsurface in order to make better decisions for economic and safe designs of the proposed structures at a Steel Rolling Factory, Ataqa Industrial Area, Northwestern Gulf of Suez, Egypt. To achieve this purpose, four seismic refraction profiles were conducted to measure the velocity of primary seismic waves (P-waves) and four profiles were conducted using Multichannel Analysis of Surface Waves (MASW) technique in the same locations of refraction profiles to measure the velocity of shear waves (S-waves). SeisImager/2D Software Package was used in the analysis of the measured data. Data processing and interpretation reflect that the subsurface section in the study area consists of two layers, the first layer is a thin surface layer ranges in thickness from 1 to 4 meters with P-wave velocity ranges from 924 m/s to 1247 m/s and S-wave velocity ranges from 530 m/s to 745 m/s. The second layer has a P-wave velocity ranges from 1277 m/s to 1573 m/s and the S-wave velocity ranges from 684 m/s to 853 m/s. Geotechnical parameters were calculated for both layers. Since elastic moduli such as Poisson’s ratio, shear modulus, Young’s modulus, and bulk’s modulus were calculated. Competence scales such as material index, stress ratio, concentration index, and density gradient were calculated also. In addition, the ultimate and allowable bearing capacities

scholarly journals СЕЙСМИЧНОСТЬ СЕВЕРНОЙ ЕВРАЗИИ в 2013 г.

2019 ◽  
pp. 11-31 ◽  
Keyword(s):  
Comparative Analysis ◽  
Sea Of Okhotsk ◽  
Great Depth ◽  
Focal Mechanisms ◽  
Northern Eurasia ◽  
Seismic Stations ◽  
The Sea Of Okhotsk ◽  
History Of ◽  
Mantle Earthquakes ◽  
Regions Of Russia

Приведен обзор сейсмичности Северной Евразии в 2013 г., включающей 15 регионов России и сопредельных стран. На указанной территории действовало 581 стационарная сейсмическая станция, из них 529 цифровых, 52 аналоговых и 8 сейсмических групп. Кроме того, в ряде регионов работали временные станции. Данными сетями зарегистрировано свыше 28 тыс. тектонических и около 6 тыс. вулканических землетрясений, для которых определены и опубликованы основные параметры. Для 595 землетрясений определены механизмы очагов. Согласно собранным в рамках ежегодника данным, в 2013 г. на территории Северной Евразии ощущались 506 землетрясений, о которых поступило более 1500 сообщений из более чем 934 населенных пунктов. Некоторые населенные пункты в течение года испытывали сотрясения несколько раз. Восемнадцать землетрясений были обследованы, результаты для большинства из них описаны в отдельных статьях данного выпуска Ежегодника, вместе с данными о механизмах очагов, предшествующей сейсмичности, особенностях афтершокового процесса и с привлечением элементов сейсмотектоники очаговых зон. В обзоре дан сравнительный анализ характеристик сейсмичности по всем 15 регионам. Сильнейшее в 2013 г. Охотоморское-III землетрясение 24 мая 2013 г. с Mw=8.3, произошедшее под акваторией Охотского моря на глубине h=630 км, явилось и крупнейшим за всю историю сейсмологических наблюдений среди мантийных землетрясений. Оно имело огромную площадь макросейсмического воздействия, но при этом из-за большой глубины нигде не вызвало разрушений. A review of the seismicity of Northern Eurasia in 2013, which includes 15 regions of Russia and neighboring countries, is presented. 581 stationary seismic stations operated in the territory, of which 529 digital, 52 analog stations and 8 seismic groups. In addition, temporary stations operated in some regions. These networks recorded over 28 thousand tectonic and about 6 thousand volcanic earthquakes, for which the main parameters were determined and published. Focal mechanisms have been determined for 595 earthquakes. According to the data collected as part of the yearbook, 506 earthquakes were felt in Northern Eurasia in 2013, of which more than 1500 messages were received from more than 934 settlements. Some settlements experienced shocks several times during the year. Eighteen earthquakes were inspected, the results for most of them are described in separate articles of this issue of the yearbook, together with data on the focal mechanisms, previous seismicity, features of the aftershock process and involving elements of seismic tectonics of focal zones. The review provides a comparative analysis of seismicity characteristics for all 15 regions. The strongest in 2013, the Okhotsk-III earthquake on May 24, 2013 with Mw=8.3 occurred under the Sea of Okhotsk with h=630 km, was also the largest in the history of seismological observations among mantle earthquakes. It had a huge area of macroseismic impact, while due to the great depth it did not cause destruction anywhere.

Structural delineation at the Los Humeros geothermal field, Mexico, by P-wave reflection retrieval from noise

2020 ◽  
Author(s):  
Arie Verdel ◽  
Boris Boullenger ◽  
Joana E. Martins ◽  
Anne Obermann ◽  
Tania Toledo ◽  
...  
Keyword(s):  
Data Retrieval ◽  
Geological Structure ◽  
Geothermal Field ◽  
Data Availability ◽  
Geothermal Reservoir ◽  
P Wave ◽  
Structural Detail ◽  
P Waves ◽  
Seismic Stations ◽  
Zero Offset

<p>The overall purpose of the recently finalized GEMex project*, a European-Mexican collaboration, has been to gain an improved understanding of the subsurface at two unconventional geothermal sites: for EGS development at Acoculco and for a superhot resource near Los Humeros. Providing a more precise description of both the geological structure and the geothermal reservoir behavior for these two sites form important requirements for achieving that goal.</p><p>For delineating the main structural features at geothermal reservoir level, reflection retrieval from ambient seismic noise can be considered interesting because of its relatively low-cost and low environmental impact as compared to more conventional, controlled-source, seismic surveying practice, where (expensive) active sources are required.</p><p>In this study, we present results from the application of ambient noise seismic interferometry (ANSI) to retrieve zero-offset reflected P-waves from continuous seismic data recorded during the second half of 2017 at the Los Humeros geothermal field, Mexico. It is known from noise interferometry theory that reflected P-waves can provide local structural detail at locations directly underneath the employed seismic stations.</p><p>We address various data selection and processing aspects related to the retrieval of these reflected P-waves. The reflections are thereafter compared with modelled reflectivities at station locations with sufficient data availability, data quality and proximity to a location at which seismic interval velocity information is available from the literature.</p><p>From our study it can be concluded that the ANSI auto-correlation technique that was applied for zero-offset reflectivity retrieval at the Los Humeros site indeed can provide relatively high structural detail: for near-horizontal reflectors in the close vicinity of the selected stations, local depth-estimates of seismic velocity-contrasts were determined. This information can be used to constrain both the geological structure and geothermal reservoir property description.</p><p>As such, results from this passive-seismic method may partially complement and partially confirm subsurface information derived from active-seismic, that can only be acquired at a higher cost, which is more labor-intensive and which has more impact on the environment.</p><p>We thank the Mexican GEMex team around Angel Figueroa Soto from UMSNH and Marco Calo from UNAM for setting up the seismic network and station maintenance as well as data retrieval. The Comisión Federal de Electricidad (CFE) kindly provided us with access to their geothermal field and permission to install the seismic stations. OGS is thanked for providing us the location details of the four active seismic lines. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727550 and the Mexican Energy Sustainability Fund CONACYT-SENER, project 2015-04-68074.</p><p>* http://www.gemex-h2020.eu/index.php?option=com_content&view=featured&Itemid=101&lang=en</p>

Geodynamic Processes Preceding the Sea of Okhotsk Deep Earthquake of May 24, 2013, with Magnitude Mw = 8.3

2019 ◽  
Vol 489 (1) ◽  
pp. 1372-1375
Author(s):  
P. P. Firstov ◽  
V. E. Glukhov ◽  
E. O. Makarov ◽  
N. A. Zharinov ◽  
N. N. Titkov ◽  
...  
Keyword(s):  
Sea Of Okhotsk ◽  
Deep Earthquake ◽  
The Sea Of Okhotsk ◽  
Geodynamic Processes

scholarly journals Specific features of earth’s free oscillations after deep-focus sea of Okhotsk earthquake of May 24, 2013

2019 ◽  
Vol 488 (6) ◽  
pp. 651-654
Author(s):  
I. P. Kuzin ◽  
L. I. Lobkovsky ◽  
K. A. Dozorova
Keyword(s):  
Sea Of Okhotsk ◽  
Strong Earthquake ◽  
Strain Energy ◽  
P Wave ◽  
Free Oscillations ◽  
P Waves ◽  
Initial Excitation ◽  
Earth’S Free Oscillations ◽  
New Interpretation ◽  
Deep Focus

A description of initial excitation of spheroidal mode 0S2 initiated by the 2013 Sea of Okhotsk earthquake (Mw= 8.3) is presented. It is based on newly revealed fact of standing P-wave origination in the epicenter of the Sea of Okhotsk earthquake and excitation of traveling surface P-waves on the Earths surface by this wave. A new interpretation of the nature of free spheroidal Earths oscillations in case of strong earthquake (М 7,5) is proposed. The spheroidal mode 0S2 is interpreted as combination of standing and traveling P-waves, transferring the Earths strain energy.

Nonlinear Rheology at Shallow Depths with Reference to the 2016 Kumamoto Earthquakes

2019 ◽  
Vol 109 (6) ◽  
pp. 2674-2690 ◽  
Author(s):  
Norman H. Sleep ◽  
Nori Nakata
Keyword(s):  
Seismic Waves ◽  
Inelastic Strain ◽  
P Wave ◽  
Seismic Velocities ◽  
P Waves ◽  
S Waves ◽  
Shallow Subsurface ◽  
Horizontal Acceleration ◽  
Normal Traction ◽  
Uppermost Layer

Abstract Strong S waves produce dynamic stresses, which bring the shallow subsurface into nonlinear inelastic failure. We examine implications of nonlinear viscous flow, which may be appropriate for shallow muddy soil, and contrast them with those of Coulomb friction within a shallow reverberating uppermost layer with low‐seismic velocities. Waves refract into essentially vertical paths at the shallow layers and produce tractions on horizontal planes. The Coulomb ratio of shear traction to lithostatic stress for S waves equals the resolved horizontal acceleration normalized to the acceleration of gravity. The ratio of dynamic vertical normal traction to lithostatic stresses is the vertical normalized acceleration from P waves. The predicted viscous inelastic strain rate in muddy soil begins at low normalized accelerations and then increases mildly and nonlinearly with increasing normalized acceleration. Failure is unaffected when P waves decrease the vertical normal traction. Seismic waves recorded at KiK‐net station KMMH16 for the 2016 Kumamoto mainshock and strong foreshock show these effects. Inelastic deformation commences at a normalized horizontal acceleration of ∼0.25 and reduces S‐ and P‐wave velocities within the uppermost ∼15  m reverberating layer. Normalized horizontal accelerations and the Coulomb stress ratio reach ∼1.25. Strong S waves arrived even when strong P waves produced vertical tension on horizontal planes. In contrast, inelastic Coulomb failure commences at a normalized horizontal acceleration equal to the effective coefficient of friction; rapid inelastic strain precludes even higher accelerations. Furthermore, horizontal planes should fail from the stresses of strong S waves during the tensional cycle of strong P waves.

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