scholarly journals Seismicity Rate Changes and Geodetic Transients in Central Apennines

2020 ◽  
Vol 47 (22) ◽  
Author(s):  
Blaž Vičič ◽  
Abdelkrim Aoudia ◽  
Alessandra Borghi ◽  
Seyyedmaalek Momeni ◽  
Alessandro Vuan
Keyword(s):  
Central Apennines ◽  
Seismicity Rate ◽  
Seismicity Rate Changes

scholarly journals Seismicity rate changes and geodetic transients in Central Apennines

2020 ◽  
Author(s):  
Blaž Vičič ◽  
Abdelkrim Aoudia ◽  
Alessandra Borghi ◽  
Seyyedmaalek Momeni ◽  
Alessandro Vuan
Keyword(s):  
Central Apennines ◽  
Seismicity Rate ◽  
Seismicity Rate Changes

scholarly journals Seismicity rate changes and geodetic transients in Central Apennines

2020 ◽  
Author(s):  
Blaž Vičič ◽  
Abdelkrim Aoudia ◽  
Alessandra Borghi ◽  
Seyyedmaalek Momeni ◽  
Alessandro Vuan
Keyword(s):  
Central Apennines ◽  
Seismicity Rate ◽  
Seismicity Rate Changes

scholarly journals Correction to: Stress and pore fluid pressure control of seismicity rate changes following the 2016 Kumamoto earthquake, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kodai Nakagomi ◽  
Toshiko Terakawa ◽  
Satoshi Matsumoto ◽  
Shinichiro Horikawa
Keyword(s):  
Fluid Pressure ◽  
Pressure Control ◽  
Pore Fluid ◽  
2016 Kumamoto Earthquake ◽  
Pore Fluid Pressure ◽  
Seismicity Rate ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Seismicity Rate Changes

An amendment to this paper has been published and can be accessed via the original article.

Consistency of teleseismic reporting since 1963

1982 ◽  
Vol 72 (1) ◽  
pp. 93-111
Author(s):  
R. E. Habermann
Keyword(s):  
Detection System ◽  
Active Regions ◽  
The United States ◽  
Western Hemisphere ◽  
Cumulative Number ◽  
Data Set ◽  
Seismicity Rate ◽  
Teleseismic Data ◽  
Entire World ◽  
Seismicity Rate Changes

abstract Changes in the rate of occurrence of smaller events have been recognized in the rupture zones of upcoming large earthquakes in several postearthquake and one preearthquake study. A data set in which a constant portion of the events in any magnitude band are consistently reported through time is crucial for the recognition of seismicity rate changes which are real (related to some process change in the earth). Such a data set is termed a homogeneous data set. The consistency of reporting of earthquakes in the NOAA Hypocenter Data File (HDF) since 1963 is evaluated by examining the cumulative number of events reported as a function of time for the entire world in eight magnitude bands. It is assumed that the rate of occurrence of events in the entire world is roughly constant on the time scale examined here because of the great size of the worldwide earthquake production system. The rate of reporting of events with magnitudes above mb = 4.5 has been constant or increasing since 1963. Significant decreases in the number of events reported per month in the magnitude bands below mb = 4.4 occurred during 1968 and 1976. These decreases are interpreted as indications of decreases in detection of events for two reasons. First, they occur at times of constant rates of occurrence and reporting of larger events. Second, the decrease during the late 1960's has also been recognized in the teleseismic data reported by the International Seismological Centre (ISC). This suggests that the decrease in the number of small events reported was related to facets of the earthquake reporting system which the ISC and NOAA share. The most obvious candidate is the detection system. During 1968, detection decreased in the United States, Central and South America, and portions of the South Pacific. This decrease is probably due to the closure of the VELA arrays, BMO, TFO, CPO, UBO, and WMO. During 1976, detection decreased in most of the seismically active regions of the western hemisphere, as well as in the region between Kamchatka and Guam. The cause of this detection decrease is unclear. These detection decreases seriously affect the amount of homogeneous background period available for the study of teleseismic seismicity rate changes. If events below the minimum magnitude of homogeneity are eliminated from the teleseismic data sets the resulting small numbers of events render many regions unsuitable for study. Many authors have reported seismicity rate decreases as possible precursors to great earthquakes. Few of these authors have considered detection decreases as possible explanations for their results. This analysis indicates that such considerations cannot be avoided in studies of teleseismic data.

scholarly journals Investigating the earthquake catalog of the National Observatory of Athens

2009 ◽  
Vol 9 (3) ◽  
pp. 905-912 ◽  
Author(s):  
G. Chouliaras
Keyword(s):  
B Value ◽  
Spatial And Temporal Variability ◽  
Earthquake Catalog ◽  
National Observatory ◽  
Data Set ◽  
Seismicity Rate ◽  
Earthquake Prediction Research ◽  
The Times ◽  
Seismicity Rate Changes ◽  
Selection Of

Abstract. The earthquake catalog of the National Observatory of Athens (NOA) since the beginning of the Greek National Seismological Network development in 1964, is compiled and analyzed in this study. The b-value and the spatial and temporal variability of the magnitude of completeness of the catalog is determined together with the times of significant seismicity rate changes. It is well known that man made inhomogeneities and artifacts exist in earthquake catalogs that are produced by changing seismological networks and in this study the chronological order of periods of network expansion, instrumental upgrades and practice and procedures changes at NOA are reported. The earthquake catalog of NOA is the most detailed data set available for the Greek area and the results of this study may be employed for the selection of trustworthy parts of the data in earthquake prediction research.

scholarly journals Seismicity rate changes in association with the evolution of the stress field in northern Aegean Sea, Greece

2012 ◽  
Vol 188 (3) ◽  
pp. 1322-1338 ◽  
Author(s):  
K. M. Leptokaropoulos ◽  
E. E. Papadimitriou ◽  
B. Orlecka-Sikora ◽  
V. G. Karakostas
Keyword(s):  
Stress Field ◽  
Aegean Sea ◽  
Seismicity Rate ◽  
Northern Aegean Sea ◽  
Seismicity Rate Changes

scholarly journals Delayed Seismicity Rate Changes Controlled by Static Stress Transfer

2017 ◽  
Vol 122 (10) ◽  
pp. 7951-7965 ◽  
Author(s):  
Kayla A. Kroll ◽  
Keith B. Richards-Dinger ◽  
James H. Dieterich ◽  
Elizabeth S. Cochran
Keyword(s):  
Stress Transfer ◽  
Static Stress ◽  
Seismicity Rate ◽  
Seismicity Rate Changes

scholarly journals Stress and pore fluid pressure control of seismicity rate changes following the 2016 Kumamoto earthquake, Japan Version 2021125

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kodai Nakagomi ◽  
Toshiko Terakawa ◽  
Satoshi Matsumoto ◽  
Shinichiro Horikawa
Keyword(s):  
Focal Mechanism ◽  
Fluid Pressure ◽  
Pore Fluid ◽  
2016 Kumamoto Earthquake ◽  
Pore Fluid Pressure ◽  
Seismicity Rate ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Seismicity Rates ◽  
Seismicity Rate Changes

AbstractWe quantitatively examined the influence of pore fluid pressure and coseismic stress changes on the seismicity rate changes that followed the 2016 Kumamoto earthquake, on the basis of two approaches. One is a numerical calculation of the classic stress metric of ∆CFS, and the other is an inversion analysis of pore fluid pressure fields with earthquake focal mechanism data. The former calculation demonstrated that seismicity rate changes were consistent with the expectation from ∆CFS in 65% of the target region, whereas they were not in the remaining 35% of the region. The latter analysis indicates that seismicity rates increased in the regions where pore fluid pressure before the Kumamoto earthquake sequence was remarkably enhanced above hydrostatic, regardless of values of ΔCFS. This suggests that the increase in pore fluid pressure is one of the important physical mechanisms triggering aftershock generation. We obtained evidence that pore fluid pressure increased around the southern part of the main rupture zone after the mainshock, examining temporal changes in types of focal mechanism data. The average increases in pore fluid pressure were estimated to be 17, 20, and 17 MPa at depths of 5, 10, and 15 km, respectively. These large increases in pore fluid pressure cannot be explained under the undrained condition. The spatial derivative of the pore fluid pressure field in the depth direction implies that fluid supply from greater depths may have controlled increases in seismicity rates that followed the large earthquake.

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