HR: 1340h
AN: S33B-1312    [Abstracts]
TI: In Search for Thermal Precursors to Earthquakes in California Using MODIS Land Surface Temperature Data
AU: * Adams, D A
EM: dadams@imageair-inc.com
AF: Imageair, Inc., 10513 Caminito Westchester, San Diego, CA 92126, United States
AU: Eneva, M
EM: meneva@imageair-inc.com
AF: Imageair, Inc., 10513 Caminito Westchester, San Diego, CA 92126, United States
AB: We test claims that earthquakes are preceded by thermal anomalies by analyzing daily nighttime land surface temperatures (LSTs) derived from data collected by the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments mounted on the Terra and Aqua satellites. Terra precedes Aqua by ~3 hours, so the LST difference between the two satellites provides an estimate of nighttime cooling/warming rates. The MODIS LST data used cover the period between 2000 and 2006 and are with ~1 km spatial resolution. They cover a 10^ox10^o tile including most of California, parts of neighboring Nevada and Arizona, and northern Mexico. Our focus is on quantifying various factors influencing the background variability of LSTs and estimating the uniqueness and statistical significance of any apparent LST anomalies. For this purpose, the LSTs and their Aqua-Terra differences are used to calculate parameters similar to the Robust Estimator of Thermal Infrared Anomalies (RETIRA) index, first described by Tramutoli (1998) and subsequently reported to show anomalously high values preceding a number of earthquakes (e.g., Tramutoli et al., 2005; Corrado et al., 2005; Genzano et al, 2007). We develop the RETIRA concept further in order to account better for meteorological and other effects on the LSTs. In particular, we quantify cloud edge effects and the effects of topography. The RETIRA index is computed for Terra LSTs, Aqua LSTs, and Aqua-Terra LST differences. We examine the relationship between M>4.5 earthquakes and anomalous RETIRA by generating movies of RETIRA time evolution. We also compare and test for statistical significance of the differences among four types of combined time periods - pre-seismic, during seismic clusters, post-seismic and seismically quiet periods. Although some statistically significant differences are established, they do not involve uniquely the pre-seismic periods and anomalies appear too ubiquitous during all types of periods to be useful for earthquake prediction. We will be further testing smaller areas around "hot spots" (Holliday and Rundle, 2005) and past earthquakes in California.
DE: 1217 Time variable gravity (7223, 7230)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
SC: Seismology [S]
MN: 2007 Fall Meeting