Artificial Water Reservoir-Triggered Earthquakes, with Special Emphasis on Koyna, India

Gupta, Harsh K.

doi:10.1007/978-3-030-10475-7_15-1

Cited by 2 publications

(7 citation statements)

References 56 publications

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“…A NNE‐SSW trending zone of surface fissures was identified in the Nanel‐Donichawadi‐Kadoli segment, a few kilometers to the south of the Koyna dam in the wake of the 1967 M ~ 6.3 Koyna earthquake (Geological Survey of India, ). Detailed seismic monitoring from a dense network of 23 surface‐based broadband stations and 6 borehole stations in the region shows a NNE‐SSW trend of seismicity that is consistent with the trend of the Donichawadi fissure zone (Gupta, ; Gupta et al, ; Shashidhar et al, ). Focal depths of earthquakes show that the fault zone dips steeply to the WNW, which was confirmed by soil‐gas helium studies followed by shallow drilling across the Donichawadi fissure zone (Gupta et al, ).…”

Section: Geologic and Tectonic Settingmentioning

confidence: 75%

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

2020

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Knowledge of the in situ stress regime is critical to investigate the genesis of recurrent triggered seismicity over the past five decades in the Koyna seismogenic zone. Orientations of in situ horizontal stresses are determined for the first time from analyses of image logs in a 3 km deep scientific borehole KFD1 in the area. KFD1 passed through 1,247 m thick Deccan Traps and continued 1,767 m in the granitic basement. Stress-induced wellbore failures, breakouts and drilling-induced tensile fractures, are identified in the acoustic and microresistivity images of the granitic basement. Additionally, tightly constrained focal mechanisms of 50 earthquakes of M ≥ 3.6, reported in literature, are inverted to constrain the stress regime. Salient results are as follows: (i) wellbore breakouts and drilling-induced tensile fractures constrain N9°W ± 17°orientation for maximum horizontal principal stress (S Hmax ); (ii) consistency with the regional NNW-SSE orientation of S Hmax from inversion of earthquake focal mechanisms shows that the borehole data are representative for the Koyna region; (iii) breakout rotations at multiple depths below 2,100 m indicate that the borehole may have passed through localized fault damage zones; (iv) consistent strike azimuths of steeply dipping fractures with S Hmax orientation indicate favorable conditions for strike-slip to normal transitional faulting environment; and (v) stress inversion of 50 well-determined earthquake focal mechanisms supports transitional faulting environment in the Koyna seismogenic zone. Thus, stress orientation and fracture information from borehole data, together with stress regime constrained from inversion of earthquake focal mechanisms, shed new light on the faulting environment in the region.

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Section: Geologic and Tectonic Settingmentioning

confidence: 75%

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

2020

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“…In our case, the Koyna‐Warna region had a complex case of RIS, involving rapid (Gupta, ) and delayed triggering of microseismicity (Simpson, ; Simpson et al, ). The granitoid basement in the region is highly fractured, as revealed from borehole core samples (Gupta et al, ; Roy et al, ) as well as relatively high levels of background seismicity (Gupta, ). Our observation is generally consistent with recent findings of remote triggering in other intraplate regions with anthropogenic activities (e.g., Han et al, ; van der Elst, Savage, et al, ; Wang et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…In the early stage, earthquakes confined to a smaller region of 20 km 2 around the Koyna Dam, but the seismicity extended further south due to the filling of the Warna reservoir in 1985 (Rastogi et al, ). Earthquakes in the region are mostly shallower than 10 km (Gupta, ; Rao & Shashidhar, ), occurring mainly in low‐velocity zones at depths of 0–1 and 5–10 km (Mandal et al, ).…”

Section: Study Regionmentioning

confidence: 99%

“…The Koyna‐Warna region has several active faults (Gupta, ), such as the Koyna River Fault and the NE‐SW trending Patan Fault in the west and the east, respectively (Figure ). In between these faults, there are many NE‐SW fractures identified from surface to hypocentral depths (Talwani, ), which are likely fluid filled and critically stressed (Gomez & Talwani, ; Rajendran et al, ; Talwani, ).…”

Section: Study Regionmentioning

confidence: 99%

“…Therefore, stress changes due to reservoir load is a secondary cause for triggering earthquake (Bell & Nur, ; Gupta, ; Roeloffs, ), which only helps in changing the fault strengths (Gupta, ; Rajendran et al, ). Gupta () found that pore pressure changes, water height filled in the reservoir, variation of water level, and duration of loading are important factors for triggering earthquakes in the region. Gomez and Talwani () found that extra stress due to pore pressures on the order of 0.3–0.6 MPa require for earthquakes triggering ≥M5.…”

Section: Study Regionmentioning

confidence: 99%

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Remote Triggering in the Koyna‐Warna Reservoir‐Induced Seismic Zone, Western India

et al. 2018

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Dynamic triggering following large distant earthquakes has been observed in many regions globally. In this study, we present evidence for remote dynamic triggering in the Koyna‐Warna region of Western India, which is known to be a premier site of reservoir‐induced seismicity. Using data from a closely spaced broadband network of 11 stations operated in the region since 2005, we conduct a systematic search for dynamic triggering following 20 large distant earthquakes with dynamic stresses of at least 1 kPa in the region. We find that the only positive cases of dynamic triggering occurred during 11 April 2012, Mw8.6 Indian Ocean earthquake and its largest aftershock of Mw8.2. In the first case, microearthquakes started to occur in the first few cycles of the Love waves, and the largest event of magnitude 3.3 occurred during the first few cycles of the Rayleigh waves. The increase of microseismicity lasted for up to five days, including a magnitude 4.8 event occurred approximately three days later. Our results suggest that the Koyna‐Warna region is stress sensitive and susceptible for remote dynamic triggering, although the apparent triggering threshold appears to be slightly higher than other regions.

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Artificial Water Reservoir-Triggered Earthquakes, with Special Emphasis on Koyna, India

Cited by 2 publications

References 56 publications

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

Remote Triggering in the Koyna‐Warna Reservoir‐Induced Seismic Zone, Western India

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