Articles | Volume 12, issue 5
Research article
21 May 2012
Research article |  | 21 May 2012

Space conditions during a month of a sequence of six M > 6.8 earthquakes ending with the tsunami of 26 December 2004

G. Anagnostopoulos and A. Papandreou

Abstract. This paper examines space and seismological data for the time period about one month before the giant Sumatra-Andaman strong (9.3) earthquake (EQ). The combination of seismological and space data reveals some interesting features for this time period: (1) six successive high speed solar wind streams obviously triggering a sudden increase of geomagnetic activity were all followed by strong to giant (M > 6.8) EQs, (2) the 6 strong EQs present certain spatial-temporal constraints, with the epicentre of the EQs occuring at the edges of the Pacific Plate (the Sumatra-Andaman EQ occurred at the end of this series of EQs, eastward of the first one), in a clockwise direction, (3) the EQs occurred after a sudden increase of geomagnetic activity, as inferred from the 3 h-Kp index, following a quiet geomagnetic period and (4) the time delay of the M > 6.2 earthquakes (in the broad area examined) from the last maximum sudden Kp increase was on average ~1.5 days. These findings from the study of the Earth's space environment during the month preceding the Sumatra-Andaman giant (9.3) EQ provide new information for a possible better understanding of the Sun-magnetosphere-lithosphere coupling.