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Chapter 05
Geological Studies
(Chandra, 1978). According to an analysis of the fault-plane solutions, there is dominance of movement on thrust planes (Fig. 8.27). Analysis of the data pertaining to the earthquakes (M 5.2-6.3) of Nepal shows the thrust faulting is accompanied by small component of strikeslip movement. It is also discovered that high stresses prevail in this sector (Gupta and Singh, 1979) with pressures directed perpendicular to the orographic trend, implying northward under thrusting along the MFT and MCT (Fitch, 1970; Srivastava, 1973; Chaudhury et al., 1976; Molnar et al., 1977; Verma et al., 1976; Chandra, 1978).
Valor
OURMA
PM
4
Fig.8.27: The fault-plane mechanisms suggest predominant thrust movements presumably
along the MBT and less commonly along the MCT. (After Verma etal., 1977).
The analysis of seismic data also indicates strike-slip movement on both MBT and the many transverse faults in the outer Lesser Himalaya (Kaila and Narain, 1976; Valdiya, 1981). It thus appears that both strike-slip and dip-slip movements are taking place along the Himalayan thrusts. In addition, the strike-slip movements are taking place on transverse faults in the Himalayan region and along the E-W trending trans current faults in the Tibetan plateau and adjoining highlands (Molnar and Tapponier, 1975). These movements represent accommodation of the crust consequent upon northerly drift of the Indian plateau. The current seismicity is an eloquent expression of the continued dynamism of the Indian plate.
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Geological investigation of rock sculptures...
