Abstract

Abstract The 26 December 2004 Sumatra-Andaman great earthquake had a −1500 km long rupture of more than 600 seconds duration, and may have involved a complex rupture process including slow slip. We processed International GNSS Service (IGS) 1-Hz Global Positioning System (GPS) data using kinematic analysis to investigate ground motion caused by this large earthquake. Since there are few 1-Hz stations, we had to process long baseline up to several thousand kilometers long. Long baselines degrade the GPS carrier phase ambiguity resolution. Nevertheless, clear seismic surface waves of the earthquake are recorded in our longdistance kinematic GPS solutions, which are in good agreement with response-corrected broadband seismic record. Our long baseline kinematic GPS solutions clearly indicated directivity of the seismic wave associated by rupture process of this earthquake. Also at the GPS stations that are 2,000 km away from the epicenter, dynamic displacements exceeding 5–10 cm were detected. In contrast, short baseline kinematic analysis shows large strain change caused by passage of surface wave, which reaches 6 × 10-6. Based on the comparison with seismometer and spectrum analysis of GPS results, it is difficult to discuss for very long time period displacement such as with a period more than 600 seconds in this study.

Highlights

  • The 26 December 2004 moment magnitude >9 Sumatra-Andaman earthquake generated a large Tsunami, which caused a devastating disaster including the loss of more than 180,000 lives. Ammon et al (2005) described the rupture process model of this earthquake based on the seismic wave analysis including long time period seismic wave

  • North-south component of the Global Positioning System (GPS) time-series deviates from the seismic record around 1,000 to 1,200 seconds after the earthquake origin

  • The seismic waves arrived in time of 800–900 seconds in both NS and EW components are interpreted to be the Raleigh waves with normal dispersion (Fig. 2). 3.2 Another GPS sites

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Summary

Introduction

The 26 December 2004 moment magnitude >9 Sumatra-Andaman earthquake generated a large Tsunami, which caused a devastating disaster including the loss of more than 180,000 lives. Ammon et al (2005) described the rupture process model of this earthquake based on the seismic wave analysis including long time period seismic wave. Ammon et al (2005) described the rupture process model of this earthquake based on the seismic wave analysis including long time period seismic wave They suggested that the northern part of the fault had a large component of slow slip, which had a 600–3500 second duration. Larson et al (2003) found good agreement between strong ground-motion records integrated to displacement and 1-Hz Global Positioning System (GPS) position estimates collected more than several hundred kilometers from the 2002 Denali earthquake epicenter. They suggested that such observations are key for studying the rupture directivity and dynamic earthquake source processes.

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