Seismic Refraction Investigation on Near Surface Landslides at the Kundasang Area in Sabah, Malaysia

Abstract

Surface geophysical method was used in studying the effect of natural disaster impact and subsurface physical changes located in an active geohazard zone at the Kundasang area in Sabah, Malaysia. The natural disaster impact was a previous surface and subsurface ground damage caused by a landslides activity, and the consequent civil engineering infrastructure failure. 2D seismic refraction tomography (2DSRT) was used in evaluating the continuous subsurface ground damage with particular reference to geomaterials and landslide features based on compressional wave (Primary velocity, vp) results. A total of four spread lines were conducted in two different zones (Northeast and Southwest zone) in Kundasang Secondary School (SMK Kundasang). Primary velocity data was acquired and recorded using ABEM Terraloc MK6 seismograph with the seismic wave being triggered by an impact and detected by arrays of sensitive devices called geophones. 2D seismic refraction primary velocity results representing subsurface profile for each survey line were calculated to determine time and depth of the subsurface profile investigated based on linear and delay time analysis supplied by Optim software package and supported by previous borehole data. The seismic refraction method identified three main layers of geomaterials which contained a subsurface landslides anomaly within the layers. The results consist of top soil/residual soil (330 600 m/s) 0 6 m, weathered zone with a mixture of soil, boulder and rock fractured (500 1900 m/s) 2 25 m and fresh rock/bedrock (> 2300 m/s) from 8 m depth. The landslides geometry was determined inconsistently within the survey line from 3 25 m (thickness), 57 and 75 m (width) and 100 m and more (length) with a primary velocity of 700 1800 m/s. The seismic refraction profiles obtained also revealed that the landslide occurrence extends from the southeast zone and continuously heading towards the northeast zone. A good matching seismic refraction results was obtained and calibrated using borehole results which shows that this technique was appropriate to be applied in near-surface landslide assessment which can further substantiates and compliments borehole data and others physical mapping * Corresponding author. Tel.: +6-013-3738-707; fax: +6-07-453-6588 . E-mail address: hazreek@uthm.edu.my .Available online at www.sciencedirect.com 517 Mohd Hazreek Zainal Abidin et al. / Procedia Engineering 50 ( 2012 ) 516 -531 data rapidly in a lower cost. Furthermore, this geophysical method adopts a surface technique that can minimise the disruption and damage to the site thus preserving a sustainable environment during the site investigation data acquisition stages.

Integrated analysis of geophysical methods for landslide characterization

“…Anatomy of SRT mechanism. is used to estimate the depths to the failure and lateral extent of the landslide (Abidin et al, 2012;Yilmaz and Kamachi, 2018). This estimation is based on differences in the physical properties of the sliding materials and the underlying undisturbed sediments or bedrock, resulting in different seismic velocities (Abramson et al, 2002).…”

Kajian Nilai Percepatan Puncak di Daerah Kulon Progo Utara, Yogyakarta, Indonesia, Berbasis Peta Gempa Nasional 2017 dan Pengukuran Mikrotremor

“…Apabila gaya gesek antar butir pada material lapukan tersebut lebih kecil daripada beban gravitasinya (umumnya akibat penambahan air dalam pori-porinya), potensi terlepasnya ikatan antar butir menjadi lebih besar [3]. Jika kondisi ini terjadi dalam daerah yang luas, luncuran tanah longsor lepas dapat mengancam infrastruktur yang berada di bawahnya [4].…”

Soil depth estimation: Part 1 - Field methods

“…O método da refração sísmica tem sido empregado em diversos estudos hidrogeológicos, como na determinação da altura do lençol freático em material não consolidado, de origem aluvial ou glacial, situado sobre aquíferos, manto rochoso ou sedimento consolidado (Haeni, 1988). Abidin et al (2012) utilizaram o método da refração sísmica em locais de deposição de escorregamentos na Malásia. Através de seus dados verificaram a ocorrência de três principais camadas que provavelmente formaram-se em decorrência da deposição de material oriundo de antigos escorregamentos.…”