1) Microzonation main Volume - Ministry Of Earth Sciences

Deterministic Seismic Hazard Analysislog( RLD ) 0.57M− 2.33(3.3)=WThe relation between moment magnitude and subsurface rupture length (RLD) was developed using reliablesource parameters and this is applicable for all types of faults, shallow earthquakes and interplate or intraplateearthquakes (Wells and Coppersmith, 1994). Using Wells and Coppersmith (1994) Equation 3.3 along with aparametric study, it is found that subsurface fault rupture length of about 3.8% of total fault length givesmoment magnitudes closely matching with the past earthquakes. Table 3.3 shows the RLD calculations,expected magnitude, and corresponding PGA from all the sources. The revised PGA lies in between minimumvalue of 0.001g and maximum value of 0.146g. In total, 9 sources have generated PGA value of more then0.045g at rock level close to Bangalore region. Among the nine sources, 3 sources have generated the higherPGA values close to Bangalore city. (i) the Arkavati fault (F47 in Figure 3.10) which is 51.24km away fromBangalore and having a length of about 125km.with a PGA of 0.025g (0.047g from RLD approach) due to anearthquake having a moment magnitude MW of 4.7. (ii) Chelur-Kolar-Battipalle Lineament (L20 in Figure3.10) having a length of about 111 km, which is 57.6km away from Bangalore causing a PGA value of0.037g(0.038g from RLD approach) due to an earthquake with M W of 5.2. (iii) Mandya-Channapatna-Bangalorelineament (L15 in Figure 3.10) having a length of about 105km which is 5.2km away from Bangalore causing aPGA value of 0.146g due to an earthquake with M W of 5.1 occurred on 16 th May 1972 (corresponds to a latitudeof 12.4 o N and longitude of 77.0 o E), RLD works out to be 3.8% of the total fault length corresponding to a PGAof 0.146g.Figure 3.10: Three seismogenic sources close to Bangalore.32