Group velocity dispersion analysis in northern Peninsular Malaysia
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ORIGINAL PAPER
Group velocity dispersion analysis in northern Peninsular Malaysia Syed Mustafizur Rahman 1 & Md. Omar Faruk 2 & Md. Habibur Rahman 3 & Mumnunul Keramat 1 & Mohd Nawawi 4 & Faisal Kamal Zaidi 5
Received: 8 November 2014 / Accepted: 15 August 2016 / Published online: 31 August 2016 # Saudi Society for Geosciences 2016
Abstract The crustal structure beneath three seismic stations over Malaysia has been investigated with the application of the group velocity dispersion analysis of the northern Sumatra earthquake data which occurred on 06 April 2010. Eighteen crustal layer models are constructed to assess the structure. Group velocity dispersions have been computed for the recorded earthquake data using a graphical method and modified Haskell matrix method for the models. Both dispersions have been presented for the interpretation of crustal layers. Findings have shown four major crustal layers having thicknesses of 2.5–4.0, 2.0–5.5, 5.0–8.0, and 8.5–9.0 km, while in Terengganu, it has shown three layers. Density, shear, and compressional wave velocities used in models have suggested that the crustal structure of the northern part of Peninsular Malaysia is crystalline. Major crustal minerals are of quartz, plagioclase, and mica. Most layers seem to have upward directions toward Perak from Kedah and Terengganu.
Keywords Crust . Group velocity . Dispersion . Model . Earthquake
Introduction Peninsular Malaysia is a part of Sundaland, which is an area of natural geologic laboratory of Southeastern Asia. It extends about 6000 km from the Andaman Islands in the northwest to the Lesser Sunda Islands in the southeast, and the Sunda is caused by subduction of the oceanic Indo-Australian plate beneath the Sunda plate, which started during the Cretaceous, i.e., ∼100 Ma ago (Hamilton 1979; Kieling et al. 2011). Asian mainland Burma, Thailand, Peninsular Malaysia, large islands of Borneo, Java, and Sumatra and their surrounding islands are the regions of Sundaland, a place of complicated intersection of the Eurasian, Indian, Australian, Pacific, and Philippine Sea plates. Northern Sumatra was formed and experienced several volcanic eruptions over the last 1.2 million years. Investigation suggests that the area is dominated by intrusive and extrusive rocks viz. granite or gabbro, adesite, or basalt, respectively, mostly covered by sedimentary unit on Sumatra. On other hand, the same volcanic rocks are directly exposed on the surface at Peninsular Malaysia (Harbury et al. 1990; Crow and Barber 2005).
* Syed Mustafizur Rahman [email protected] Md. Omar Faruk [email protected] Md. Habibur Rahman [email protected] Mumnunul Keramat [email protected] Mohd Nawawi [email protected]
Faisal Kamal Zaidi [email protected] 1
Department of Applied Physics and Electronic Engineering, University of Rajshahi, Rajshahi 6205, Bangladesh
2
Department of ICE, Pabna University of Science and Technology, Pabna 6600, Bangladesh
3
CEGIS, Dhaka 1212, Bangladesh
4
School of Physics, Universiti Sains Malaysia, 11800 USM, Gelugor, Pula
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