Earthquakes began to occur in Koyna region （India） soon after the filling of Koyna Dam in 1962. In the present study, three datasets 1964-1993, 1993-1995, and 1996-1997 are analyzed to study the b-value and fractal ...Earthquakes began to occur in Koyna region （India） soon after the filling of Koyna Dam in 1962. In the present study, three datasets 1964-1993, 1993-1995, and 1996-1997 are analyzed to study the b-value and fractal dimension. The b-value is calculated using the Gutenberg- Richter relationship and fractal dimension Dcorr. using correlation integral method. The estimated b-value and Dcorr. of this region before 1993 are found to be in good agreement with previously reported studies. In the sub- sequent years after 1995, the b-value shows an increase. The estimated b-values of this region are found within the limits of global average. Also, the pattern of spatial clustering of earthquakes show increase in clustering and migration along the three zones called North-East Zone, South-East Zone （SEZ）, and Warna Seismic Zone. The earthquake events having depth ≤5 km are largely confined to SEZ. After 1993, the Dcorr. shows decrease, implying that earth- quake activity gets clustered. This seismic clustering could be helpful for earthquake forecasting.展开更多
Late Cenozoic fluvial stratigraphic records of the Himalayan foreland basin–the Siwalik Group between Rivers Ganga and Ravi were studied and reviewed to understand the responses of allogenic forcing at variable timef...Late Cenozoic fluvial stratigraphic records of the Himalayan foreland basin–the Siwalik Group between Rivers Ganga and Ravi were studied and reviewed to understand the responses of allogenic forcing at variable timeframe.The Siwalik succession represents an upward stratigraphic coarsening sequence which was initiated~13 Ma and terminated and deformed by the Himalayan Frontal Thrust(HFT)at around 0.2 Ma.展开更多
文摘Earthquakes began to occur in Koyna region （India） soon after the filling of Koyna Dam in 1962. In the present study, three datasets 1964-1993, 1993-1995, and 1996-1997 are analyzed to study the b-value and fractal dimension. The b-value is calculated using the Gutenberg- Richter relationship and fractal dimension Dcorr. using correlation integral method. The estimated b-value and Dcorr. of this region before 1993 are found to be in good agreement with previously reported studies. In the sub- sequent years after 1995, the b-value shows an increase. The estimated b-values of this region are found within the limits of global average. Also, the pattern of spatial clustering of earthquakes show increase in clustering and migration along the three zones called North-East Zone, South-East Zone （SEZ）, and Warna Seismic Zone. The earthquake events having depth ≤5 km are largely confined to SEZ. After 1993, the Dcorr. shows decrease, implying that earth- quake activity gets clustered. This seismic clustering could be helpful for earthquake forecasting.
文摘Late Cenozoic fluvial stratigraphic records of the Himalayan foreland basin–the Siwalik Group between Rivers Ganga and Ravi were studied and reviewed to understand the responses of allogenic forcing at variable timeframe.The Siwalik succession represents an upward stratigraphic coarsening sequence which was initiated~13 Ma and terminated and deformed by the Himalayan Frontal Thrust(HFT)at around 0.2 Ma.
