Detection of gravity changes before powerful earthquakes in GRACE satellite observations
Main Article Content
Abstract
The variations of gravity field have been analyzed in this article, in order to find disturbances in the vicinity of recent great earthquakes epicenters including Chile (February 27, 2010), Tohoku-Oki (March 11, 2011) and Indian Ocean (April 11, 2012) prior to the events. For this purpose, the 10 years long time series of gravitational gradient components obtained from weekly Gravity Recovery And Climate Experiment (GRACE) solutions have been used. Some of gravitational gradient components are independent to GRACE stripy error and amplify high frequency components of gravity field. Therefore that preseismic activity can be better illustrated. The interquartile method has been used to construct the higher and lower bounds in time series to detect outlying solution outside the bounds associated with impending earthquakes. Afterwards, Nonlinear Auto-Regressive models with eXogenous inputs (NARX) neural network has been proposed in the detection process of prominent gravity field anomalies prior the earthquakes. Both methods detect considerable anomalous occurrences during 2-5 weeks prior to the earthquakes. Our results statistics show that the anomalous deviations before the earthquakes have different signs and amplitudes at different cases.
Article Details
Open-Access License
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.