A geometric frequency–magnitude scaling transition: Measuring b=1.5 for large earthquakes

2012 ◽  
Vol 532-535 ◽  
pp. 167-174 ◽  
Author(s):  
Mark R. Yoder ◽  
James R. Holliday ◽  
Donald L. Turcotte ◽  
John B. Rundle
Keyword(s):  
Magnitude Scaling ◽  
Large Earthquakes ◽  
Frequency Magnitude

The intermediate earthquake source near Bucaramanga, Colombia

1970 ◽  
Vol 60 (1) ◽  
pp. 269-276 ◽  
Author(s):  
Eysteinn Tryggvason ◽  
James Edwards Lawson
Keyword(s):  
Point Source ◽  
Seismic Source ◽  
Earthquake Source ◽  
Intermediate Depth ◽  
Intermediate Earthquake ◽  
Large Earthquakes ◽  
Frequency Magnitude

abstract An intensive source of intermediate depth earthquakes has been located in northern Colombia. The activity of this source increased significantly between 1956 and 1966, but appears to be decreasing after 1966. The frequency-magnitude relation of the Bucaramanga earthquakes is anomalous, with fewer large earthquakes than expected. The distribution of determined hypocenters is the same as would be observed if all earthquakes originated in the same point source. Therefore it is concluded that the Bucaramanga seismic source consists of a volume, less than 10 km in radius, centered at 6.8°N, 73.1°W., and 150 km depth.

Spatial Variations of Seismic B-Values Distribution in China

2011 ◽  
Vol 71-78 ◽  
pp. 4819-4822
Author(s):  
Jie Xu ◽  
G. Lacidogna
Keyword(s):  
Material Properties ◽  
Heterogeneous Material ◽  
Spatial Variations ◽  
Shallow Depth ◽  
B Values ◽  
Large Earthquakes ◽  
Frequency Magnitude ◽  
Earthquake Data ◽  
Values Distribution

Seismic frequency-magnitude relationship has been investigated in China, based on the earthquake data in the range ofM3.0 toM7.0 during the years 1986-2008, to study the potential of variations ofb-values with the depth. According to the results, there is a systematic decrease inbvalue with increasing depth of earthquakes. At the shallow depth conditions, with more heterogeneous material properties and lower lithosphere stress prevail, rupture initiation is more likely to stop before accumulating into large earthquakes, producing relatively smaller earthquakes and consequently higherb-values. On the contrary, the larger earthquakes are more likely to happen at a greater depth.

Modeling the Difference in Ground-Motion Magnitude-Scaling in Small and Large Earthquakes

2011 ◽  
Vol 82 (4) ◽  
pp. 504-508 ◽  
Author(s):  
J. Douglas ◽  
P. Jousset
Keyword(s):  
Ground Motion ◽  
Magnitude Scaling ◽  
The Difference ◽  
Large Earthquakes

Anomalies in continuous GPS data as precursors of 15 large earthquakes in Western North America during 2007-2016

2019 ◽  
Vol 13 (1) ◽  
pp. 163-174
Author(s):  
Nan Li ◽  
Xiangzeng Kong ◽  
Ling Lin
Keyword(s):  
North America ◽  
Gps Data ◽  
Western North America ◽  
Continuous Gps ◽  
Large Earthquakes

scholarly journals Forecasting the Locations of Future Large Earthquakes: An Analysis and Verification

2010 ◽  
Vol 167 (6-7) ◽  
pp. 743-749 ◽  
Author(s):  
Robert Shcherbakov ◽  
Donald L. Turcotte ◽  
John B. Rundle ◽  
Kristy F. Tiampo ◽  
James R. Holliday
Keyword(s):  
Large Earthquakes

scholarly journals Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra

2007 ◽  
Vol 7 (5) ◽  
pp. 625-628 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
P.-F. Biagi ◽  
M. Hayakawa
Keyword(s):  
Gravity Waves ◽  
Fresnel Zone ◽  
Signal Amplitude ◽  
Magnetic Storms ◽  
Frequency Range ◽  
Atmospheric Gravity Waves ◽  
Period Range ◽  
Before And After ◽  
Atmospheric Gravity ◽  
Large Earthquakes

Abstract. We analyze variations of the LF subionospheric signal amplitude and phase from JJY transmitter in Japan (F=40 kHz) received in Petropavlovsk-Kamchatsky station during seismically quiet and active periods including also periods of magnetic storms. After 20 s averaging, the frequency range of the analysis is 0.28–15 mHz that corresponds to the period range from 1 to 60 min. Changes in spectra of the LF signal perturbations are found several days before and after three large earthquakes, which happened in November 2004 (M=7.1), August 2005 (M=7.2) and November 2006 (M=8.2) inside the Fresnel zone of the Japan-Kamchatka wavepath. Comparing the perturbed and background spectra we have found the evident increase in spectral range 10–25 min that is in the compliance with theoretical estimations on lithosphere-ionosphere coupling by the Atmospheric Gravity Waves (T>6 min). Similar changes are not found for the periods of magnetic storms.

scholarly journals Investigation of Pre-Earthquake Ionospheric and Atmospheric Disturbances for Three Large Earthquakes in Mexico

Geosciences ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Christina Oikonomou ◽  
Haris Haralambous ◽  
Sergey Pulinets ◽  
Aakriti Khadka ◽  
Shukra R. Paudel ◽  
...  
Keyword(s):  
Chemical Potential ◽  
Atmospheric Model ◽  
Satellite System ◽  
Seismic Events ◽  
Electron Content ◽  
Total Electron ◽  
Atmospheric Disturbances ◽  
Global Ionospheric Maps ◽  
Global Navigation Satellite ◽  
Large Earthquakes

The purpose of the present study is to investigate simultaneously pre-earthquake ionospheric and atmospheric disturbances by the application of different methodologies, with the ultimate aim to detect their possible link with the impending seismic event. Three large earthquakes in Mexico are selected (8.2 Mw, 7.1 Mw and 6.6 Mw during 8 and 19 September 2017 and 21 January 2016 respectively), while ionospheric variations during the entire year 2017 prior to 37 earthquakes are also examined. In particular, Total Electron Content (TEC) retrieved from Global Navigation Satellite System (GNSS) networks and Atmospheric Chemical Potential (ACP) variations extracted from an atmospheric model are analyzed by performing statistical and spectral analysis on TEC measurements with the aid of Global Ionospheric Maps (GIMs), Ionospheric Precursor Mask (IPM) methodology and time series and regional maps of ACP. It is found that both large and short scale ionospheric anomalies occurring from few hours to a few days prior to the seismic events may be linked to the forthcoming events and most of them are nearly concurrent with atmospheric anomalies happening during the same day. This analysis also highlights that even in low-latitude areas it is possible to discern pre-earthquake ionospheric disturbances possibly linked with the imminent seismic events.

scholarly journals Stress relaxation arrested the mainshock rupture of the 2016 Central Tottori earthquake

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yoshihisa Iio ◽  
Satoshi Matsumoto ◽  
Yusuke Yamashita ◽  
Shin’ichi Sakai ◽  
Kazuhide Tomisaka ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Focal Mechanism ◽  
Large Earthquake ◽  
Static Stress ◽  
Focal Mechanism Solutions ◽  
Large Earthquakes

AbstractAfter a large earthquake, many small earthquakes, called aftershocks, ensue. Additional large earthquakes typically do not occur, despite the fact that the large static stress near the edges of the fault is expected to trigger further large earthquakes at these locations. Here we analyse ~10,000 highly accurate focal mechanism solutions of aftershocks of the 2016 Mw 6.2 Central Tottori earthquake in Japan. We determine the location of the horizontal edges of the mainshock fault relative to the aftershock hypocentres, with an accuracy of approximately 200 m. We find that aftershocks rarely occur near the horizontal edges and extensions of the fault. We propose that the mainshock rupture was arrested within areas characterised by substantial stress relaxation prior to the main earthquake. This stress relaxation along fault edges could explain why mainshocks are rarely followed by further large earthquakes.

scholarly journals A Methodology of Workshops to Explore Mutual Assistance Activities for Earthquake Disaster Mitigation

2021 ◽  
Vol 18 (7) ◽  
pp. 3814
Author(s):  
Kazuki Karashima ◽  
Akira Ohgai
Keyword(s):  
Disaster Management ◽  
Quantitative Evaluation ◽  
Management Plan ◽  
Suggested Method ◽  
Disaster Mitigation ◽  
Earthquake Disaster ◽  
Support Tool ◽  
Mutual Assistance ◽  
Large Earthquakes

To minimize the damage caused by large earthquakes, mutual assistance activities between residents and rescue victims (i.e., to support residents who cannot evacuate individually) are important. To enhance these activities, the technologies and methods for creating a Community Disaster Management Plan (CDMP), based on the quantitative evaluation of mutual assistance abilities, are required. However, the lack of a method for it is a key issue. This study aims to develop a methodology of workshops for making CDMPs by using the developed support tool by the authors to explore and promote mutual assistance activities. Through the demonstration and examination of a Community Disaster Management Plan on actual districts, the findings mentioned in this article were obtained. Moreover, the usability of this method is shown. In particular, this method is effective at revising CDMPs, and raising resident awareness on the importance of mutual assistance. The suggested method can also improve the lack of techniques involved in promoting mutual assistance.

Fuzzified time-frequency method for identification and localization of power system faults

2021 ◽  
pp. 1-13
Author(s):  
Pullabhatla Srikanth ◽  
Chiranjib Koley
Keyword(s):  
Power System ◽  
High Accuracy ◽  
Fuzzy Decision ◽  
Frequency Method ◽  
Time Frequency ◽  
Novel Approach ◽  
S Transform ◽  
Different Types ◽  
Power System Faults ◽  
Frequency Magnitude

In this work, different types of power system faults at various distances have been identified using a novel approach based on Discrete S-Transform clubbed with a Fuzzy decision box. The area under the maximum values of the dilated Gaussian windows in the time-frequency domain has been used as the critical input values to the fuzzy machine. In this work, IEEE-9 and IEEE-14 bus systems have been considered as the test systems for validating the proposed methodology for identification and localization of Power System Faults. The proposed algorithm can identify different power system faults like Asymmetrical Phase Faults, Asymmetrical Ground Faults, and Symmetrical Phase faults, occurring at 20% to 80% of the transmission line. The study reveals that the variation in distance and type of fault creates a change in time-frequency magnitude in a unique pattern. The method can identify and locate the faulted bus with high accuracy in comparison to SVM.

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