indo–us workshop on “intraplate seismicity” - The CERI Blog

Fig. 2: Seismic activity near the Warna reservoir during 2009 and 2010. A and B are the two
areas, where intense clustering is visible. XX’ is the P-­‐wave velocity section shown in Figure
3.
Currently, a drilling project in the area is in a first conceptual planning phase. Tentatively, it
is planned to be placed close to the Warna reservoir where the seismic activity has been
most intense during the past two years (Figure 2). A 3D velocity model has been developed
based on the operation of 97 seismic stations in the vicinity of the Koyna and the Warna
reservoirs. This site of the proposed bore hole is located close to the location of the recent
intense seismic activity (Figure 3). Depth sections for blocks A and B are shown in Figure 4. A
deep borehole would provide direct observational data on the composition, physical state
and mechanical behavior of a major active fault zone at focal depths of RTS. It would also be
possible to test and constrain RTS hypotheses, faulting and earthquake generation in an
intra-­‐plate seismic zone, and contribute to earthquake hazard reduction. Down-­‐hole
measurements complemented by observations on cores and cuttings, analyses of fluid and
gas samples, geophysical and geological site characterization studies including fault zone
monitoring would help answer questions related to the genesis of RTS.