Temporal and spatial analyses on seismo-electric anomalies associated with the 27 February 2010 <i>M</i> = 8.8 Chile earthquake observed by DEMETER satellite

Abstract

Abstract. This paper studies seismo-electromagnetic anomalies observed by the French satellite DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) during the 27 February 2010 M = 8.8 Chile earthquake. The nighttime electron density (Ne), electron temperature (Te), ion density (Ni), ion temperature (Ti) and whistler counts (Cw) are investigated. A statistical analysis of the box-and-whisker method is applied to see if data of two or more groups under study are significantly different. A cross-examination of temporal variations before and after shows that Ne and Ni (Cw) increases (decreases) appear 10–20 days before the earthquake. A comparison of data over the epicenter and those over its reference area can be employed to discriminate the earthquake-related anomalies from global effects. Results prove that anomalous enhancements of Ne, Ni, and Ti occur specifically around the epicenter area. The intersection of the temporal and spatial results confirms that Ne and Ni are useful and sensitive detecting anomalous related to the 2010 M = 8.8 Chile earthquake.