HR: 1340h
AN: S23A-0229    [Abstracts]
TI: Unified Scaling Law for Earthquakes: Mega-cities and urban agglomerations
AU: Nekrasova, A
EM: nastia@mitp.ru
AF: International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, 79-2 Warshavskoye Shosse, Moscow, 117556 Russian Federation
AU: * Kossobokov, V
EM: volodya@mitp.ru
AF: International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, 79-2 Warshavskoye Shosse, Moscow, 117556 Russian Federation
AU: * Kossobokov, V
EM: volodya@mitp.ru
AF: Institute de Physique du Globe de Paris, 4 Place Jussieu, Paris, 75252 France
AB: The confirmed fractal nature of earthquakes and their distribution in space implies that traditional estimations of seismic hazard for cities and urban agglomerations are usually underestimated. The evident patterns of distributed seismic activity follow the Unified Scaling Law that generalizes Gutenberg-Richter recurrence relation. The results of the systematic global analysis of the local earthquake size distribution imply that (i) the recurrence of earthquakes in a seismic region, for a wide range of magnitudes and sizes is characterized with the following law: Log N(M,L) = A - B (M - 5) + C Log L, where N(M,L) is the expected annual number of earthquakes of magnitude M within an area of liner size L; (ii) for a wide range of control parameter A from under -1.0 to above 0.5, which value determines the average rate of earthquakes that accordingly differs by a factor of 30 or more, the balance between magnitude ranges, B, resides mainly from 0.6 to 1.1, while the fractal dimension of the local seismic prone setting, C, changes from under 1 to 1.4 and larger; (iii) any estimate of earthquake recurrence rate depends on the size of the territory that is used for averaging and, therefore, differ dramatically when scaled down in proportion to the area of interest. Stabilized version of a robust box-counting algorithm was used to map the values of A, B, and C in every place on the Earth, where the US GS/NEIC Global Hypocenters' Data Base permits a reliable estimation. Using these basic characteristics of earthquake distribution the recurrence rates of moderate, strong, major, and great earthquakes are estimated for each mega-city or an urban agglomeration situated in seismically active territories worldwide. The results are compared to traditionally scaled estimates based on the observed recurrence rates in the extended neighborhoods of a mega-city. The general level of such an underestimation of the rates is too large for being ignored in seismic risk and earthquake loss evaluations necessary for a knowledgeable disaster prevention and mitigation.
DE: 1872 Time series analysis (3270, 4277, 4475)
DE: 3270 Time series analysis (1872, 4277, 4475)
DE: 4277 Time series experiments (1872, 3270, 4475)
SC: Seismology [S]
MN: Fall Meeting 2005