Leveraging on multidisciplinary expertise for landslide disaster risk reduction and management : a case study of a limestone hill rockfall hazard assessment, Batu Caves, Selangor, Malaysia

The United Nations Development Program agenda 2030 has charted out seventeen Sustainable Development Goals (SDG) whereby Malaysia as a member has strategically set the platform for growth. From the seventeen agendas, the SDG 9 (built resilient, promote inclusive and sustainable industrialization and foster innovation) and SDG 11 (make cities and human settlements inclusive, resilient, and sustainable) requires a paradigm shift from conventional engineering approach for environmentally induced disasters. Leveraging multidisciplinary ability and information and communications technology (ICT) in the landslide disaster studies had enabled regional-scale information acquirement for hazards identification, exposure, and risk assessment to meet the goals. The investigated limestone hill, Batu Caves is located within the suburban city of Kuala Lumpur. The land use around the hill is extensive and the area is highly populated with encroachment to the toe of the limestone hill. The purpose of the risk study was to assess the limestone hill’s stability and hazards and the exposure that may lead to the vulnerability of the residences and commercial activities at and around the hill. Therefore, an engineering risk assessment study was carried out to determine rock fall hazard potential. The Terrestrial Laser Scanning survey was utilized to obtain the hillside’s cross section. Discontinuity mapping was conducted to identify rock block size and rock slope was analyzed using rock mass classification system to determine rock slope quality. The rockfall analysis was conducted to identify rock rollout distance and produce rock fall hazard maps. The Slope Mass Rating for the slope BC1A, Parcel 1, Batu Caves was determined as 61, and is classified as a partially stable. The maximum rollout distance at this slope was 11 m. This illustrates the practical output of this study that can be applied for mitigation and future development of the area

Beberapa hasil penyiasatan geofizik di kawasan Bachok, Kelantan

Keseluruhan kawasan Bachok merupakan endapan aluvium. Endapan ini mempunyai tiga akuifer pada kedalaman 0 - 5 meter, 15 - 30 meter dan 40 - 60 meter. Kajian geofizik pada tahap awal yang merangkumi aspek seismos biasan, seismos pantulan dan kerintangan geoelektrik telah dilakukan untuk menyiasat ketebalan dan kedalaman akuifer, kedalaman batu dasar dan kemasinan air tanah. Hasil kajian menunjukkan bahawa teknik seismos biasan telah dapat menghasilkan maklumat mengenai kedudukan akuifer pertama. manakala teknik seismos pantulan menghasilkan maklumat terperinci mengenai akuifer kedua dan ketiga serta batu dasar. Nilai kerintangan geoelektrik rendah bagi akuifer pertama menunjukkan sama ada disebabkan oleh intrusi air masin atau kehadiran lempung samudera

Effectiveness of Geoelectrical Resistivity Surveys for the Detection of a Debris Flow Causative Water Conducting Zone at KM 9, Gap-Fraser’s Hill Road (FT 148), Fraser’s Hill, Pahang, Malaysia

This study reports the findings of resistivity surveys which were conducted at the initiation area of debris flow at KM 9, Fraser’s Hill Gap road (FT148). The study involves three slope parallel survey lines and two lines perpendicular to the slope face. The parallel lines are FH01, FH02, and FH03, while the lines FH04 and FH05 are perpendicular. A granite body was detected at the central part of the east line and is nearest to the ground surface along FH02. The existence of low resistivity zones within the granite body is interpreted as highly fractured, water conducting zones. These zones are continuous as they have been detected in both the east-west as well as the north-south lines. The residual soil layer is relatively thin at zones where weathered granite dominates the slope face of the failure mass. The weak layer is relatively thick with an estimated thickness of 80 m and water flow occurs at the base of it. The high water flow recorded from the horizontal drains further supports the possible existence of these highly fractured, water conducting zones located within the granite. The shallow fractured granite is virtually “floating” above the water saturated zone and therefore is considered unstable