scholarly journals A detailed analysis of some local earthquakes at Somma-Vesuvius

1999 ◽  
Vol 42 (3) ◽  
Author(s):  
P. Capuano ◽  
U. Coppa ◽  
G. De Natale ◽  
F. Di Sena ◽  
C. Godano ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Frequency Band ◽  
Seismic Activity ◽  
Focal Mechanisms ◽  
Ground Acceleration ◽  
Spectral Parameters ◽  
Seismic Stations ◽  
Local Earthquakes ◽  
Seismic Swarms ◽  
Order Of Magnitude

In this paper, we analyze local earthquakes which occurred at Somma-Vesuvius during two episodes of intense seismic swarms, in 1989 and 1995 respectively. For the selected earthquakes we have computed accurate hypocentral locations, focal mechanisms and spectral parameters. We have also studied the ground acceleration produced by the largest events of the sequences (ML 3.0), at various digital stations installed in the area during the periods of higher seismic activity. The main result is that seismicity during the two swarm episodes presents similar features in both locations and focal mechanisms. Strong site dependent effects are evidenced in the seismic radiation and strong amplifications in the frequency band 10-15 Hz are evident at stations located on the younger Vesuvius structure, with respect to one located on the ancient Somma structure. Furthermore, seismic stations show peak accelerations for the same events of more than one order of magnitude apart.

scholarly journals Double difference relocation of local earthquakes in the Nepal Himalaya

2013 ◽  
Vol 46 ◽  
Author(s):  
S. Rajaure ◽  
S. N. Sapkota ◽  
L. B. Adhikari ◽  
B. Koirala ◽  
M. Bhattarai ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Focal Mechanisms ◽  
Double Difference ◽  
Simple Explanation ◽  
Fault Plane Solutions ◽  
Motion Data ◽  
Local Earthquakes ◽  
Microseismic Activity ◽  
Narrow Belt ◽  
Himalayan Tectonics

Interseismic strain across the Himalaya is associated with intense microseismic activity. In this study we analyze in detail this seismicity to explore in more details how it relates to Himalayan tectonics. We use the Double Difference Relocation Method to relocate local earthquakes recorded by National Seismological Centre in the period between 1995 and 2003. We also determined fault plane solutions for 10 earthquakes based on waveforms modeling and first P-motion data to complement the existing dataset of focal mechanisms. The results depict a narrow belt of intense seismic activity, at depth between 10 and 20km, which can be traced all along the topographic front of the Higher Himalaya in Nepal. This zone coincides with the zone of interseismic strain build up at the down dip end of the locked portion of the Main Himalayan Thrust fault. These earthquakes probably activate minor faults within the Himalayan wedge, in a volume which experiences stress build up in the interseismic period. The intense seismic activity generally cease abruptly as the elevation of topography gets higher than 3500 m. This elevation also coincides with a change of tectonic regime. Earthquakes within the seismicity belt at front of the Higher Himalaya are of thrust type indicating N-S shortening. Where the topographic elevation is higher than 3500 m focal mechanisms indicate E-W extension. The effect of topography on the regional stress field thus provides a simple explanation for the distribution of focal mechanisms and the seismicity cut-off at the 3500m elevation contour line.

scholarly journals SAKHALIN

2019 ◽  
pp. 173-183 ◽  
Author(s):  
T. Fokina ◽  
D. Safonov ◽  
D. Kostylev ◽  
V. Mikhaylov
Keyword(s):  
Seismic Activity ◽  
Strong Earthquake ◽  
Focal Mechanisms ◽  
The South ◽  
The West ◽  
Seismic Stations ◽  
Macroseismic Effect ◽  
Deep Earthquakes ◽  
Background Seismicity ◽  
Increased Activity

The review of seismicity for Sakhalin in 2013 based on the data of four seismic stationary stations and 10 temporary digital seismic stations "DAT", working in the south of Sakhalin, is given. The main parameters of 688 earthquakes and focal mechanisms of five of them are determined. 42 earthquakes showed a macroseismic effect. The maps of the representativeness of earthquakes and of epicenters are given, the distribution of crust and deep earthquakes on the magnitude and their summarized energy for seven seismoactive districts are presented. For each area, seismic conditions are described. The seismicity of the Sakhalin region in 2013 can be characterized as moderate. Somewhat increased seismic activity was recorded in the East Sakhalin region, against the background seismicity in previous years. Somewhat increased activity was also recorded in the West Sakhalin region, where a moderately strong earthquake occurred with MLH=5.1.

scholarly journals SAKHALIN

2020 ◽  
pp. 152-161
Author(s):  
T. Fokina ◽  
D. Safonov ◽  
D. Kostylev ◽  
V. Mikhaylov
Keyword(s):  
Seismic Activity ◽  
Focal Mechanisms ◽  
Local Network ◽  
Seismic Events ◽  
Regional Network ◽  
Strong Earthquakes ◽  
Seismic Regime ◽  
Seismic Stations ◽  
Macroseismic Effect

A review of the Sakhalin seismicity in 2014 based on the data of regional network is given. The network included four stationary and ten temporary digital seismic stations. This network was supported by ten stations of local network operating in the south of Sakhalin. Parameters of 450 seismic events, including 25 explosions, and focal mechanisms for 4 events are determined. 22 earthquakes had a macroseismic effect. The map of earthquake completeness and the map of epicenters are given. The distribution of crust and deep earthquakes on magnitude and their summarized energy for seven seismoactive areas in comparison with average parameters for 2001–2013 are presented. For each area and the region as a whole, an analysis of the seismic regime parameters in 2014 in comparison with long-term parameters is given, tangible and strong earthquakes are described. The seismicity of the Sakhalin region in 2014 can be characterized as a moderate one. Somewhat increased seismic activity was recorded in the East Sakhalin and Southeastern areas.

scholarly journals ARMENIA

2020 ◽  
pp. 61-67
Author(s):  
Heghine Sargsyan ◽  
Gohar Abgaryan ◽  
Edgar Mughnetsyan ◽  
Ani Gevorgyan
Keyword(s):  
Seismic Activity ◽  
Focal Mechanisms ◽  
P Wave ◽  
Seismic Stations ◽  
Macroseismic Effect ◽  
The North ◽  
The Republic ◽  
Spitak Earthquake ◽  
Focal Zone

The article describes changes in the composition and equipment of the network of seismic stations in Armenia, which ensured a representative level of earthquake registration in Armenia in 2014 with K3min=8.0. The analysis of seismicity on the territory of Armenia and neighboring regions is carried out, focal mechanisms of 17 earthquakes are determined using the signs of P-wave first arrivals at the seismic stations of Armenia and neighboring countries. Within the Republic, the highest level of seismic activity in 2014 was in the North, in the focal zone of Spitak earthquake 07.12.1988 with MLH=6.8, I0=10. The macroseismic effect of earthquakes felt in Armenia is described.

Source parameters and focal mechanisms of local earthquakes: Single broadband observatory at ISM Dhanbad

2009 ◽  
Vol 74 (3) ◽  
pp. 413-419 ◽  
Author(s):  
J. R. Kayal ◽  
V. K. Srivastava ◽  
S. N. Bhattacharya ◽  
P. K. Khan ◽  
Rima Chatterjee
Keyword(s):  
Source Parameters ◽  
Focal Mechanisms ◽  
Local Earthquakes

scholarly journals Total Dose Effects on 4H-SiC Bipolar Junction Transistors

2017 ◽  
Vol 897 ◽  
pp. 579-582
Author(s):  
Sethu Saveda Suvanam ◽  
Luigia Lanni ◽  
Bengt Gunnar Malm ◽  
Carl Mikael Zetterling ◽  
Anders Hallén
Keyword(s):  
Total Dose ◽  
Detailed Analysis ◽  
Surface Recombination ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Displacement Damage ◽  
Base Current ◽  
Dose Effects ◽  
Order Of Magnitude ◽  
Total Dose Effects

In this work, total dose effects on 4H-SiC bipolar junction transistors (BJT) are investigated. Three 4H-SiC NPN BJT chips are irradiated with 3MeV protons with a dose of 1×1011, 1×1012 and 1×1013 cm-2, respectively. From the measured reciprocal current gain it is observed that 4H-SiC NPN BJT exposed to protons suffer both displacement damage and ionization, whereas, a traditional Si BJT suffers mainly from displacement damage. Furthermore, bulk damage introduction rates for SiC BJT were extracted to be 3.3×10-15 cm2, which is an order of magnitude lower compared to reported Si values. Finally, from detailed analysis of the base current at low injection levels, it is possible to distinguish when surface recombination leakage is dominant over bulk recombination.

scholarly journals Seismogenic ancient structures of the central and northern part of the East European platform

2019 ◽  
Vol 489 (4) ◽  
pp. 405-408
Author(s):  
V. V. Adushkin ◽  
I. A. Sanina ◽  
G. N. Ivanchenko ◽  
E. M. Gorbunova ◽  
I. P. Gabsatarova ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Activity ◽  
East European Platform ◽  
Historical Earthquakes ◽  
Seismic Array ◽  
Small Aperture ◽  
Seismic Stations ◽  
East European

The analysis of the location of the epicenters of earthquakes that occurred in the central and northern part of the East European platform in 2009-2016, recorded by the seismic stations of the GS RAS and the small aperture seismic array of IGD RAS Mikhnevo was performed. The results obtained indirectly indicate the seismic activity of the Riphean structures of the region, disturbing the surface of the basement, and their possible activation at the present time. Available data on historical earthquakes also confirm their relevance to paleorifts. It seems important to take into account the position of the ancient aulacogens in assessing the seismic hazard of the East European platform.

Temporal evolution of relative seismic velocity in the Golf of Corinth - Greece.

2021 ◽  
Author(s):  
Estelle Delouche ◽  
Laurent Stehly
Keyword(s):  
Lower Crust ◽  
Seismic Noise ◽  
Seismic Velocity ◽  
Temporal Evolution ◽  
Velocity Variation ◽  
Extension Rate ◽  
Fluid Migration ◽  
Seismic Stations ◽  
Gulf Of Corinth ◽  
Seismic Swarms

<p>Our aim is to monitor the temporal evolution of the crust in Greece, with a particular focus on the Gulf of Corinth.  Indeed, Greece is one of the most exposed country to earthquakes in Europe. The Gulf of Corinth,  is known for its fast extension rate of about 15 mm/yr in the western part and 10mm/yr in the eastern part. This fast extension is associated with recurrent seismic swarms and by a few destructive earthquakes. This seismicity is likely the result of a combination of multiple driving processes including fluid migration at depth.</p><p>In the present work, we use seismic noise recorded from 2010 to 2020 by all seismic stations deployed in Greece, and in particular by the dense Corinth Rift Laboratory network, to compute the seismic velocity variation (dv/v) in several subregions. By comparing the result obtained at different periods, we are able to distinguish the temporal evolution of the upper, mid and lower crust. This temporal evolution is compared to the seismicity of the Gulf of Corinth.</p>

Seismic Hazard Estimation in East China Offshore Areas

2013 ◽  
Vol 690-693 ◽  
pp. 1158-1167
Author(s):  
Li Fang Zhang ◽  
Yan Ju Peng ◽  
Zhen Ming Wang
Keyword(s):  
Seismic Hazard ◽  
Seismic Activity ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
East China ◽  
Earthquake Catalog ◽  
Ground Acceleration ◽  
Study Region ◽  
Seismicity Model ◽  
Seismic Hazard Estimation

In this study, we chose East China offshore areas as study region(N25°~41°，E117°~126°).According to the tectonic environments and characteristics of earthquake the seismotectonic units were established, taking Gaussian spatially smoothing only based on the input earthquake catalog, and fault-rupture-oriented elliptical smoothing to calculate the seismic activity rate in each cells. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained through using the method of seismic hazard analysis based on cell source. While the total number of earthquakes unchanged, two-stage smoothing procedure deals with the error of epicenter location, contains the seismotectonic information in elliptical smoothing seismicity model. This method build up a simple and easy methodology of probabilistic seismic hazard analysis, especially for those place where not yet been clearly master the seismic tectonic information and with distributed Seismic activity.

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