Delineation of Active Faults, Nucleation Process and Pore Pressure Measurements at Koyna (India)

Chadha, R. K.; Gupta, Harsh K.; Kümpel, Hans‐Joachim; Mandal, Prantik; Rao, A. Nageswara; Kumar, Narendra; Radhakrishna, I.; Rastogi, B. K.; Raju, I. P.; Sarma, C. S. P.; Satyamurthy, C.; Satyanarayana, H. V. S.

doi:10.1007/978-3-0348-8814-1_11

Cited by 10 publications

(17 citation statements)

References 13 publications

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“…Focal mechanisms and moment tensor inversions indicate complexly faulted basement underlying the Deccan Traps in the Koyna-Warna area, with general agreement of strike-slip movement on one or more NE-SW trending faults and normal faulting on NW-SE oriented faults [Rastogi and Talwani, 1980;Gupta et al, 1980;Langston, 1976Langston, , 1981Langston and Franco-Spera, 1985;Dziewonski et al, 1988;Chadha et al, 1997;Mandal et al, 1998;Gahalaut et al, 2004;Dura-Gomez and Talwani, 2010]. One of the NNE-SSW trending faults is believed to be the strike-slip causative fault for the 10 December 1967 M 6.3 Koyna earthquake, but to the south, the NW-SE oriented faults are predominantly normal faults that coincide with the general trend of the Warna lineament [Singh et al, 1975;Langston, 1976Langston, , 1981Gupta et al, 1980;Rastogi and Talwani, 1980;Langston and Franco-Spera, 1985;Talwani, 1997b;Rastogi et al, 1997;Gahalaut et al, 2004;Shashidhar et al, 2011].…”

Section: 1002/2014jb010950mentioning

confidence: 99%

“…There have been 22 earthquakes of M > 5, about 200 earthquakes of M~4, and several thousand smaller earthquakes since 1962. Since the early 1960s, multiple seismicity studies have been carried out in this region to understand seismotectonics of the Koyna-Warna area [Gupta et al, 1969;Guha et al, 1971;Langston, 1981;Rastogi and Talwani, 1980;Langston and Franco-Spera, 1985;Rajendran et al, 1996;Chadha et al, 1997;Gupta et al, 1997;Talwani et al, 1996;Talwani, 1997b;Rastogi et al, 1997;Mandal et al, 1998;Rai et al, 1999;Rastogi and Mandal, 1999;Rajendran and Harish, 2000;Gahalaut et al, 2004;Srinagesh and Sarma, 2005;Sarma and Srinagesh, 2007;Shashidhar et al, 2011]. However, data for most of the previous studies were recorded with relatively few seismographs, and few 3-D velocity models have previously been correlated with the events.…”

Section: Introductionmentioning

confidence: 99%

“…As more reliable data became available over time, locations steadily improved. Studies by Rajendran et al [1996], Chadha et al [1997], and Mandal et al [1998] provided much improved locations, but their hypocentral locations, like many of the previous studies, included timing and location errors associated with the seismograph network, and they lacked a detailed velocity model. As a result, their focal depth errors typically ranged from 2 to 3 km or more [Rai et al, 1999].…”

Section: Introductionmentioning

confidence: 99%

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Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

et al. 2014

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Although seismicity near Koyna Reservoir (India) has persisted for~50 years and includes the largest induced earthquake (M 6.3) reported worldwide, the seismotectonic framework of the area is not well understood. We recorded~1800 earthquakes from 6 January 2010 to 28 May 2010 and located a subset of 343 of the highest-quality earthquakes using the tomoDD code of Zhang and Thurber (2003) to better understand the framework. We also inverted first arrivals for 3-D Vp, Vs, and Vp/Vs and Poisson's ratio tomography models of the upper 12 km of the crust. Epicenters for the recorded earthquakes are located south of the Koyna River, including a high-density cluster that coincides with a shallow depth (<1.5 km) zone of relatively high Vp and low Vs (also high Vp/Vs and Poisson's ratios) near Warna Reservoir. This anomalous zone, which extends near vertically to at least 8 km depth and laterally northward at least 15 km, is likely a water-saturated zone of faults under high pore pressures. Because many of the earthquakes occur on the periphery of the fault zone, rather than near its center, the observed seismicity-velocity correlations are consistent with the concept that many of the earthquakes nucleate in fractures adjacent to the main fault zone due to high pore pressure. We interpret our velocity images as showing a series of northwest trending faults locally near the central part of Warna Reservoir and a major northward trending fault zone north of Warna Reservoir.

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Section: 1002/2014jb010950mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

et al. 2014

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“…Monitoring wells have been installed along fault zones to observe water level changes as an indicator of crustal deformation and to search for possible pre-seismic abnormal changes in the United States , Japan (Igarashi and Wakita, 1991;Ohno and Wakita, 1997), India (Chadha et al, 1997), and elsewhere. The number of groundwater level records in the vicinity of Chelungpu fault and the magnitude of waterlevel changes induced by the Chi-Chi earthquake, however, may be unprecedented.…”

Section: Introductionmentioning

confidence: 99%

Changes of Groundwater Level due to the 1999 Chi-Chi Earthquake in the Choshui River Alluvial Fan in Taiwan

Chia

Wang

Chiu

et al. 2004

Bulletin of the Seismological Society of America

114

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Changes of groundwater levels induced by the M L 7.3 Chi-Chi earthquake on 21 September 1999 were recorded at 157 out of 179 monitoring wells in the Choshui River alluvial fan. Of those, 67 observed large groundwater-level changes, ranging from 1.0 to 11.1 m. These 157 wells are clustered at 64 stations located approximately 2 to 50 km west of the north-south-trending Chelungpu fault. Both oscillatory and steplike changes of water level were observed on the analog records at the time of earthquake, while only steplike changes were observed on the hourly digital records. Coseismic changes of groundwater level were recorded not only in the confined aquifers but also in the partially confined aquifers and the unconfined aquifers. The recovery of water-level changes took minutes to months, depending primarily on hydrogeologic conditions of the confining layers. The sign and magnitude of coseismic water-level change at a well varied with its distance from the fault. The distribution of coseismic water-level changes induced by the ChiChi earthquake indicates that water-level rise predominated in most of the footwall area, whereas water-level fall prevailed in a narrow zone adjacent to the fault trace.

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“…Formation properties such as groundwater flow rate, electromagnetic fields, hydrogeochemical and tilt-strain components, and others, have been observed and considered as precursors to earthquakes (Tohjima et al, 1994;Depuev and Zelenova, 1996;Dal Moro et al, 2000;Tzanis et al, 2000;Kingsley et al, 2001;Fujinawa et al, 2002). Studies have demonstrated that the changes in water levels in the wells are closely related to pore-pressure changes and fault creep (Nason and Weertman, 1973;Johnson et al, 1973;Wesson, 1981;Chadha et al, 1997). Bredehoeft (1967) showed that groundwater levels can respond to a small strain in the earth's crust, implying that water levels in the wells could be observed to monitor stress changes along active fault zones, and may be a potential precursor of earthquakes (Kovach et al, 1975).…”

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confidence: 99%

Time series decomposition of groundwater level changes in wells due to the Chi‐Chi earthquake in Taiwan: a possible hydrological precursor to earthquakes

Gau

Chen

et al. 2007

Hydrological Processes

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Abstract:The largest and most disastrous earthquake in Taiwan (Mw: 7Ð3) in the 20th century, the Chi-Chi earthquake, hit central Taiwan at 01 : 47 local time on September 21, 1999. The groundwater level changes were rapid at that time. Studies have found that the rapid change in groundwater levels was a co-seismic phenomenon. This work analyzes the possibility that the abnormal change in groundwater levels may have occurred before the earthquake. Three well stations with a total of five wells are considered. They are all near the Che-Lung-Pu fault, which caused the Chi-Chi earthquake. The time series decomposition method was applied to decompose the seasonal groundwater level, the trend in groundwater levels, and the period of the change in the groundwater level. Residual groundwater levels were found by subtracting the determined seasonal, trend and period data from corresponding data for the original groundwater level. The computed residual water levels in July, August and September of 1999, were transformed into a frequency spectrum by a Fourier method. Additionally, the effects of barometric pressures on the groundwater level changes were also evaluated. Analytical results show that the spectral density functions of the irregular groundwater level in the confined aquifer at the Chu-Shan well in September behaved differently from those in July and August. We posit that a pre-seismic hydrogeological anomaly may have existed before the Chi-Chi earthquake, and can be considered in future studies of anomalies associated with earthquakes.

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Delineation of Active Faults, Nucleation Process and Pore Pressure Measurements at Koyna (India)

Cited by 10 publications

References 13 publications

Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

Seismicity, faulting, and structure of the Koyna‐Warna seismic region, Western India from local earthquake tomography and hypocenter locations

Changes of Groundwater Level due to the 1999 Chi-Chi Earthquake in the Choshui River Alluvial Fan in Taiwan

Time series decomposition of groundwater level changes in wells due to the Chi‐Chi earthquake in Taiwan: a possible hydrological precursor to earthquakes

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