Accelerating seismicity and stress accumulation before large earthquakes

2001 ◽  
Vol 28 (21) ◽  
pp. 4039-4042 ◽  
Author(s):  
David D. Bowman ◽  
Geoffrey C. P. King
Keyword(s):  
Large Earthquakes ◽  
Stress Accumulation

Increasing critical sensitivity of the Load/Unload Response Ratio before large earthquakes with identified stress accumulation pattern

2006 ◽  
Vol 428 (1-4) ◽  
pp. 87-94 ◽  
Author(s):  
Huai-zhong Yu ◽  
Zheng-kang Shen ◽  
Yong-ge Wan ◽  
Qing-yong Zhu ◽  
Xiang-chu Yin
Keyword(s):  
Response Ratio ◽  
Accumulation Pattern ◽  
Large Earthquakes ◽  
Stress Accumulation

Seismicity in the Tsengwen reservoir area, Taiwan

1979 ◽  
Vol 69 (6) ◽  
pp. 1783-1796
Author(s):  
Francis T. Wu ◽  
Y. H. Yeh ◽  
Y. B. Tsai
Keyword(s):  
Water Level ◽  
Earthquake Swarm ◽  
Tectonic Stress ◽  
Thrust Fault ◽  
Time Study ◽  
Surrounding Area ◽  
Storage Volume ◽  
Loading Effects ◽  
Large Earthquakes ◽  
Stress Accumulation

abstract The Tsengwen reservoir, with a maximum depth of 128 m, and a storage volume of 708 × 106 m3, is located over an active thrust fault, the Chuko Fault. The Chuko Fault was evidently the causative fault of a magnitude 634 (Pasadena, MS earthquake in 1964. Filling of the reservoir started in April 1973 and water reached the designed level in September of that same year; since then, the water level has undergone yearly cycles with 40 to 50 m amplitude. An earthquake swarm occurred near the dam in December 1972, before the filling of the reservoir, and microearthquakes in the area have been monitored for various periods since that time. Before filling, there were some very shallow events, with depths less than 2.5 km, but these disappeared shortly after the water level rose to the maximum. The majority of hypocenters after reservoir loading lie in a layer between depths of 2.5 and 8 km; the seismicity under the reservoir is noticeably lower than that in the surrounding area. There is no obvious correlation of seismicity with water level, based on available data. The seismicity in the Tsengwen area can be described as a response of the over-pressured and fractured sedimentary strata to the tectonic stress accumulation, modified by the loading effects of the reservoir. A ts/tp versus time study revealed anomalies, but these are not precursory to large earthquakes, as the duration of the anomalies would imply.

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.

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