EARTHQUAKE MAXIMUM MAGNITUDE ESTIMATION CONSIDERING REGIONAL SEISMOTECTONIC PARAMETERS

The objective of this paper is to estimate the maximum magnitude (𝑀𝑚𝑎𝑥) which is defined as the upper limit of earthquake magnitude for a given region by a new approach considering regional rupture characteristics. The proposed method has been explained in details and examined for an active seismic region. Seismic study area (SSA) has been generated by dividing into radii of 200 km and 500 km, based on the seismicity and seismotectonics. The regional rupture character has been established by considering Percentage Fault Rupture (PFR), which is the ratio of subsurface rupture length (RLD) to Total Fault Length (TFL) expressed in percentage. PFR is used for determining RLD, which is further used for estimating the maximum magnitude for each source. Maximum magnitude for SSA of Kanpur region has been estimated and compared with the 𝑀𝑚𝑎𝑥 values from existing methods. It is observed from the study that the existing deterministic and probabilistic 𝑀𝑚𝑎𝑥 estimation methods are sensitive to SSA radius, magnitude of completeness (𝑀𝑐 ), ‘𝑎’ and ‘𝑏’ parameters and 𝑀𝑚𝑎𝑥 𝑜𝑏𝑠 values. However, 𝑀𝑚𝑎𝑥 from the proposed method is a function of the rupture character and is irrespective of the SSA and 𝑀𝑐, ‘𝑎’ and ‘𝑏’ parameters and 𝑀𝑚𝑎𝑥 𝑜𝑏𝑠 values.