Landslides are one of the most frequent disasters which occur widespread in Indonesia. This disaster often causes damages and fatalities. One of the mitigations efforts to reduce potential loss is by predicting the area affected by landslide movement. This research developed a numerical model of landslide movement by incorporating the erosion and deposition laws along the flow path. This model improves the accuracy of the previous models which assume that landslide volume is constant without any consideration for the erosion and deposition. The governing equation of this newly developed model uses the Eulerian numerical approach based on the finite difference scheme. The erosion-deposition laws applied in this research are from Egashira et al. (2001), McDougall and Hungr (2005), and Blanc (2008). The simulation program applies Python programming language and examines an imaginary slope with ellipsoid-shaped of source area. The simulation result shows that the additional erosion-deposition formula can enlarge the volume and the affected area of landslide movement. It is clarified that the erosion rate is a determinant factor affecting the results of calculation.

Landslides often cause heavy casualties and material losses in Tanggamus Regency. These incidentscontinue to be repeated so that it still requires a landslides risk reduction. Landslides risk mitigation begins with a field survey and soil investigation, followed by analyzing the investigation results and planning the potential mass movements. The results from the geological survey show that the study area has a lithology of constituents in the form of andesite and landslide material in the form of volcanic breaks with a high level of weathering so as to form a thick layer of soil. The basic landslide handling design plan in Pekon Waykerap is to perform the geometry arrangement of the slopes so itprovides a strengthened structure with gabion slopes. The slope design results give the slope height limited to 5 meters, a 1H:1V slope gradient, and 2.5 meter bench. The slope surface is suggested to be covered with a patch of grass and equipped with surface drainage. The slope stability analysis results for Pekon Waykerap landslides using the limit equilibrium method shows that using the combination of control and retrofitting method and increases the static safety factor from 1.092 to 1.298 and the dynamic safety factor from 0.846 to 1.031, which means the groundmass movement risk decreases.

No abstract

No abstract

Tanah longsor adalah salah satu bencana hidrometeorologi yang paling sering terjadi di Indonesia. Kondisi alam berupa perbukitan dengan pegunungan terjal dan dipicu oleh kondisi geografis yang beriklim tropis menyebabkan daerah ini sering mengalami bencana longsor. Sebagian besar daerah yang terpapar bencana tersebut menimpa pemukiman penduduk di pedesaan yang memiliki tingkat aksesibilitas yang kurang baik, tingkat pendidikan rendah dan tingkat ekonomi menengah ke bawah. Kejadian ini salah satunya terdapat di Kelurahan Pidada, Kecamatan Panjang, Kota Bandar Lampung. Penelitian ini menjelaskan investigasi longsor yang dilakukan pada beberapa titik longsor yang terjadi di Gang Sakal, Kelurahan Pidada. Analisis stabilitas lereng dilakukan menggunakan metode keseimbangan batas berupa irisan Morgenstern_Price berdasarkan data hasil pengukuran dan investigasi geoteknik. Dengan demikian, evaluasi stabilitas lereng dilakukan untuk memberikan penilaian terhadap kondisi aktual daerah studi dan memberikan alternatif mitigasi yang tepat. Hasil penelitian menyimpulkan bahwa, dengan tindakan mitigasi yang akurat dan terencana, lokasi rawan longsor dapat stabil. Upaya mitigasi yang baik dapat mengurangi risiko kerugian yang ditimbulkan di masa yang akan datang.