Seismicity at Warna reservoir (near Koyna) through 1995

A point process procedure can be used to study reservoir-induced seismicity (RIS), in which the intensity function representing earthquake hazard is a combination of three terms: a constant background term, an ETAS (epidemic-type aftershock sequence) term for aftershocks, and a time function derived from observation of water levels of a reservoir. This paper presents the results of such a study of the seismicity in the vicinity of the Tarbela reservoir in Pakistan. Making allowance for changes in detection capability and the background seismicity related to tectonic activity, earthquakes of magnitude ≥ 2.0, occurring between May 1978 and January 1982 and whose epicentres were within 100 km of the reservoir, were used in this analysis. Several different intensities were compared via their Akaike information criterion (AIC) values relative to those of a Poisson process. The results demonstrate that the seismicity within 20 km of the reservoir correlates with water levels of the reservoir, namely, active periods occur about 250 days after the appearance of low water levels. This suggests that unloading the reservoir activates the seismicity beneath it. Seasonal variations of the seismicity in an area up to 100 km from the reservoir were also found, but these could not be adequately interpreted by an appropriate RIS mechanism.

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Point process modelling of reservoir-induced seismicity

Journal of Applied Probability ◽

10.1017/s0021900200112811 ◽

2001 ◽

Vol 38 (A) ◽

pp. 232-242

Author(s):

Masajiro Imoto

Keyword(s):

Point Process ◽

Induced Seismicity ◽

Earthquake Hazard ◽

Information Criterion ◽

Aftershock Sequence ◽

Water Levels ◽

Tectonic Activity ◽

Reservoir Induced Seismicity ◽

Epidemic Type Aftershock Sequence ◽

Background Seismicity

A point process procedure can be used to study reservoir-induced seismicity (RIS), in which the intensity function representing earthquake hazard is a combination of three terms: a constant background term, an ETAS (epidemic-type aftershock sequence) term for aftershocks, and a time function derived from observation of water levels of a reservoir. This paper presents the results of such a study of the seismicity in the vicinity of the Tarbela reservoir in Pakistan. Making allowance for changes in detection capability and the background seismicity related to tectonic activity, earthquakes of magnitude ≥ 2.0, occurring between May 1978 and January 1982 and whose epicentres were within 100 km of the reservoir, were used in this analysis. Several different intensities were compared via their Akaike information criterion (AIC) values relative to those of a Poisson process. The results demonstrate that the seismicity within 20 km of the reservoir correlates with water levels of the reservoir, namely, active periods occur about 250 days after the appearance of low water levels. This suggests that unloading the reservoir activates the seismicity beneath it. Seasonal variations of the seismicity in an area up to 100 km from the reservoir were also found, but these could not be adequately interpreted by an appropriate RIS mechanism.

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On the b-value Dependency of Injection-Induced Seismicity on Geomechanical Parameters

10.1002/essoar.10507492.1 ◽

2021 ◽

Author(s):

Yusuke mukuhira ◽

Takatoshi Ito ◽

Michael Fehler ◽

Elvar K Bjarkason ◽

Hiroshi Asanuma ◽

...

Keyword(s):

Induced Seismicity ◽

B Value ◽

Geomechanical Parameters

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Reservoir-induced Seismicity in Brazil

The Mechanism of Induced Seismicity ◽

10.1007/978-3-0348-8179-1_25 ◽

2002 ◽

pp. 597-617 ◽

Cited By ~ 1

Author(s):

Marcelo Assumpção ◽

Vasile Marza ◽

Lucas Barros ◽

Cristiano Chimpliganond ◽

José Eduardo Soares ◽

...

Keyword(s):

Induced Seismicity ◽

Reservoir Induced Seismicity

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Two types of reservoir-induced seismicity

Bulletin of the Seismological Society of America ◽

10.1785/bssa0780062025 ◽

1988 ◽

Vol 78 (6) ◽

pp. 2025-2040

Author(s):

D.W. Simpson ◽

W.S. Leith ◽

C.H. Scholz

Keyword(s):

Normal Stress ◽

Pore Pressure ◽

Induced Seismicity ◽

Elastic Stress ◽

Pore Space ◽

Temporal Distribution ◽

The Other ◽

Elastic Response ◽

Reservoir Induced Seismicity ◽

Effective Normal Stress

Abstract The temporal distribution of induced seismicity following the filling of large reservoirs shows two types of response. At some reservoirs, seismicity begins almost immediately following the first filling of the reservoir. At others, pronounced increases in seismicity are not observed until a number of seasonal filling cycles have passed. These differences in response may correspond to two fundamental mechanisms by which a reservoir can modify the strength of the crust—one related to rapid increases in elastic stress due to the load of the reservoir and the other to the more gradual diffusion of water from the reservoir to hypocentral depths. Decreased strength can arise from changes in either elastic stress (decreased normal stress or increased shear stress) or from decreased effective normal stress due to increased pore pressure. Pore pressure at hypocentral depths can rise rapidly, from a coupled elastic response due to compaction of pore space, or more slowly, with the diffusion of water from the surface.

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Historical and recent seismic activity in South Carolina

Bulletin of the Seismological Society of America ◽

10.1785/bssa0620030851 ◽

1972 ◽

Vol 62 (3) ◽

pp. 851-864 ◽

Cited By ~ 3

Author(s):

G. A. Bollinger

Keyword(s):

South Carolina ◽

Seismic Activity ◽

B Value ◽

Low Noise ◽

The State ◽

Seismic Zone ◽

Recurrence Relationship ◽

Noise Data ◽

History Of ◽

Felt Area

Abstract The seismic history of South Carolina is dominated by the great Charleston earthquake of August 31, 1886. In addition to having several unusual aspects (region essentially free from shocks for preceding 200 years, large felt area, dual epicenter points, “low intensity zone” in West Virginia), that intensity X event seriously perturbed the seismic regime of the area for at least the following 30 years. Of 438 earthquakes reported to have occurred in the state between 1754 and 1971, 402 have been in the Charleston-Summerville area. The remaining 36 shocks form a southeasterly-trending zone of activity that is transverse to the structural grain of the Appalachians. For the 60 shocks assigned an intensity value (1886-1971), a recurrence relationship between the number of earthquakes “N” of maximum intensity “I0” was found to be log N = 0.52-0.31 I0 for IV ≦ I0 ≦ VIII. This corresponds to a “b” value of 0.5 ± 0.1 in log N versus M relationship assuming M = 1 + (2/3)I0. These data suggest a frequency of seismic activity comparable to that reported for the New Madrid seismic zone. Three months of microearthquake monitoring in the Charleston area during the summer of 1971 yielded 505 hr of low-noise data. Sixty-one earthquakes, primarily in swarm occurrence, were recorded. An h value of 1.8 ± 0.5 was determined for these microshock events. This value is similar to that previously observed for a swarm sequence in New Jersey. Four shocks occurred in the state during 1971. Three of these events (May 19, July 31, August 11) were in the central part of the state near Orangeburg, while the third event (July 13) was near Seneca in northwestern South Carolina. All three events had 3.0 < ML < 4.0. Similar episodes of three or four shocks in 1 year happened in 1956 and again in 1965. The Orangeburg area had, according to historical data, been previously free of earthquake epicenters.

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