A Probabilistic Estimate of the Most Perceptible Earthquake Magnitudes in the NW Himalaya and Adjoining Regions

作者：Yadav R B S^*; Koravos G Ch; Tsapanos T M; Vougiouka G E

来源：Pure and Applied Geophysics, 2015, 172(2): 197-212.

DOI：10.1007/s00024-014-0864-1

• Perceptibility
• seismic hazard
• ground motion attenuation relation
• NW Himalaya

NW Himalaya and its neighboring region (25A degrees-40A degrees N and 65A degrees-85A degrees E) is one of the most seismically hazardous regions in the Indian subcontinent, a region that has historically experienced large to great damaging earthquakes. In the present study, the most perceptible earthquake magnitudes, M (p), are estimated for intensity I = VII, horizontal peak ground acceleration a = 300 cm/s(2) and horizontal peak ground velocity v = 10 cm/s in 28 seismogenic zones using the two earthquake recurrence models of Kijko and Sellevoll (Bulletin of the Seismological Society of America 82(1):120-134 1992 ) and Gumbel's third asymptotic distribution of extremes (GIII). Both methods deal with maximum magnitudes. The earthquake perceptibility is calculated by combining earthquake recurrence models with ground motion attenuation relations at a particular level of intensity, acceleration and velocity. The estimated results reveal that the values of M (p) for velocity v = 10 cm/s show higher estimates than corresponding values for intensity I = VII and acceleration a = 300 cm/s(2). It is also observed that differences in perceptible magnitudes calculated by the Kijko-Sellevoll method and GIII statistics show significantly high values, up to 0.7, 0.6 and 1.7 for intensity, acceleration and velocity, respectively, revealing the importance of earthquake recurrence model selection. The estimated most perceptible earthquake magnitudes, M (p), in the present study vary from M (W) 5.1 to 7.7 in the entire zone of the study area. Results of perceptible magnitudes are also represented in the form of spatial maps in 28 seismogenic zones for the aforementioned threshold levels of intensity, acceleration and velocity, estimated from two recurrence models. The spatial maps show that the Quetta of Pakistan, the Hindukush-Pamir Himalaya, the Caucasus mountain belt and the Himalayan frontal thrust belt (Kashmir-Kangra-Uttarkashi-Chamoli regions) exhibit higher values of the most perceptible earthquake magnitudes (M (W) > 6.0). These spatially-distributed values indicate good agreement with high seismic hazard zones in previously published hazard maps based on seismicity, maximum expected earthquake magnitudes during specific time intervals and maximum expected acceleration. These maps have useful implications in preparing earthquake selection criteria for the anti-seismic design of non-critical structures in the study region.

• 出版日期2015-2