Crustal deformation study in Peninsular Malaysia using global positioning system

Abstract

From the Global Positioning System (GPS) measurement over a large part of South East-Asia in 1994 – 1996 showed that Sundaland is a stable tectonic block with velocity 12 ± 3 mm/yr moving relatively to East – South East respectively to Eurasia. In December, 2004 and March, 2005 there were two big megathrust earthquakes occurred near to the west coast Aceh with 9.3 Mw and Nias with 8.7 Mw. These earthquakes had caused deformation on the stable Sundaland. Due to first earthquake, the GPS station in the northern part of Peninsular Malaysia deform until 17 cm and the southern part until 1 cm. In order to understand the deformation that caused by those earthquakes, it is necessary to study the tectonic setting of Peninsular Malaysia and measurements through GPS. The tectonic setting of Peninsular Malaysia shows that Peninsular Malaysia is divided into two tectonic blocks; and beside that Peninsular Malaysia also has a few major faults which crossing the Peninsular Malaysia from north to south, and west to east. GPS data over the Peninsular Malaysia and 30 International GPS Services (IGS) stations over the world from 2004 until 2008 were used to measure the deformation. From the measurement showing that several co-seismic during 2004 until 2008 indicated that north-west of Peninsular Malaysia suffer the worse deformation than the other place. The post-seismic motions always change in the magnitude and directions. The other side there were some phenomena recorded in Peninsular Malaysia such as sink hole in Ipoh and Batu Gajah, tremors in Bukit Tinggi area (2007-2008) and tremor at Jerantut (2009). The combination from GPS measurement with those phenomena indicated that there is a seismic activity going on this land. Because of that it is necessary to carry out the combine research which is not only focusing on GPS but also another tool such as micro gravity, seismic and so on which could improve the understanding of the structure and deformation of Peninsular Malaysia.