Electrical Resistivity Survey in Bukit Bunuh, Malaysia for Subsurface Structure of Meteorite Impact Study

摘要

An electrical resistivity tomography (ERT) study was conducted at Bukit Bunuh, Lenggong Perak (Malaysia). The study is to justify the features and environmental subsurface geological structure which is due to the meteorite impact. The ERT survey used resistivity equipments comprises of 4 survey lines with 5 m electrode intervals, covering an area of approximately 64 km2. The survey lines were carried out using ‘roll-along’ technique. The data were processed and analysed using RES2DINV, Excel and Surfer software in order to produce electrical resistivity tomography for qualitative interpretations. The results show the variation of resistivity value and faults. The 2-D resistivity results generally show the study area was divided into two main zones, alluvium with resistivity value of 10 - 800 Ωm, and bedrock with resistivity value of > 1500 Ωm and depth of 20 - 40 m. There are lots of fractured zones which are different than normal, identified along the survey lines. The South-North line shows the fractured zones were identified at 760 - 3800 m and 4700 - 5900 m. The West-East line, the fractured zone was identified at 1545 - 6570 m and North-West to South-East line, the fractured zone was identified at 740 - 5850 m. Meanwhile, South-West to North-East line, the fractured zone was identified at 720 - 1520 m. These interesting results were indicated at position of longitude;100.965 - 100.978 and latitude;5.056 - 5.066 where the bedrock depth is 40 - 60 m MSL and highly fractured. The area was surrounded by high elevated bedrock. Integration of 2-D resistivity results with boreholes is successful give valid and reliable results. The results of the study indicate that these geophysical approaches have a capability of retrieving the meteorite impact subsurface of the studied area.