Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia

Lake Toba, the largest lake in Sumatra Island, is a volcanic lake that holds great significance both geologically and culturally. It has a breathtaking natural wonder that captivates visitors from around the world. The fluctuation of surface levels in Lake Toba adds another layer of complexity to th...

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Main Authors: Ariani, Listia, Faris, Fikri, Rifa'i, Ahmad
Format: Article
Language:English
Published: GEOMATE International Society 2023
Subjects:
Online Access:https://repository.ugm.ac.id/285824/1/GEOTECHNICAL%20ASSESSMENT%20OF%20SUBLAKE%20SLOPES%20AND%20LIQUEFACTION.pdf
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author Ariani, Listia
Faris, Fikri
Rifa'i, Ahmad
author_facet Ariani, Listia
Faris, Fikri
Rifa'i, Ahmad
author_sort Ariani, Listia
collection UGM
description Lake Toba, the largest lake in Sumatra Island, is a volcanic lake that holds great significance both geologically and culturally. It has a breathtaking natural wonder that captivates visitors from around the world. The fluctuation of surface levels in Lake Toba adds another layer of complexity to the stability of its sublake slopes during seismic activity. The key aim of this paper is to study the sublake slope stability, likelihood of liquefaction potential, and permanent deformation that subject to the fluctuation of Lake Toba surface levels. This research was conducted the numerical analysis of GeoStudio 2022.1 software by combining QUAKE/W, SLOPE/W, and SIGMA/W to evaluate the pre- and post-earthquake condition. The slope stability in the pre-earthquake condition was stable regardless of the reduced safety factor along with the declining lake surface level, but in the post-earthquake condition the safety factor was reduced nearly 60%, resulting in slope instability. An earthquake exhibits 0.25 g of acceleration within a period of 44.435 s, caused liquefaction up to 7.7 m layer of soil structure and high amplification of the ground surface approximately to 0.44 g. Massive permanent deformation occurred as the result were varying from 7 m to 12.1 m. As the surface level decreases, potential for liquefaction decreases as well but the safety factor value of slope stability increases, which can lead to a greater increase in the potential for permanent deformation. This indicates that the declining of the lake surface level influences slope failure during an earthquake.
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spelling oai:generic.eprints.org:2858242024-03-06T02:26:29Z https://repository.ugm.ac.id/285824/ Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia Ariani, Listia Faris, Fikri Rifa'i, Ahmad Civil Engineering not elsewhere classified Civil Engineering Engineering Lake Toba, the largest lake in Sumatra Island, is a volcanic lake that holds great significance both geologically and culturally. It has a breathtaking natural wonder that captivates visitors from around the world. The fluctuation of surface levels in Lake Toba adds another layer of complexity to the stability of its sublake slopes during seismic activity. The key aim of this paper is to study the sublake slope stability, likelihood of liquefaction potential, and permanent deformation that subject to the fluctuation of Lake Toba surface levels. This research was conducted the numerical analysis of GeoStudio 2022.1 software by combining QUAKE/W, SLOPE/W, and SIGMA/W to evaluate the pre- and post-earthquake condition. The slope stability in the pre-earthquake condition was stable regardless of the reduced safety factor along with the declining lake surface level, but in the post-earthquake condition the safety factor was reduced nearly 60%, resulting in slope instability. An earthquake exhibits 0.25 g of acceleration within a period of 44.435 s, caused liquefaction up to 7.7 m layer of soil structure and high amplification of the ground surface approximately to 0.44 g. Massive permanent deformation occurred as the result were varying from 7 m to 12.1 m. As the surface level decreases, potential for liquefaction decreases as well but the safety factor value of slope stability increases, which can lead to a greater increase in the potential for permanent deformation. This indicates that the declining of the lake surface level influences slope failure during an earthquake. GEOMATE International Society 2023 Article PeerReviewed application/pdf en https://repository.ugm.ac.id/285824/1/GEOTECHNICAL%20ASSESSMENT%20OF%20SUBLAKE%20SLOPES%20AND%20LIQUEFACTION.pdf Ariani, Listia and Faris, Fikri and Rifa'i, Ahmad (2023) Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia. International Journal of GEOMATE, 25 (111). pp. 153-161. ISSN 21862990 https://geomatejournal.com/geomate/article/view/4077/3298 10.21660/2023.111.4077
spellingShingle Civil Engineering not elsewhere classified
Civil Engineering
Engineering
Ariani, Listia
Faris, Fikri
Rifa'i, Ahmad
Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title_full Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title_fullStr Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title_full_unstemmed Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title_short Geotechnical Assessment of Sublake Slopes and Liquefaction Hazard in Lake Toba, Indonesia
title_sort geotechnical assessment of sublake slopes and liquefaction hazard in lake toba indonesia
topic Civil Engineering not elsewhere classified
Civil Engineering
Engineering
url https://repository.ugm.ac.id/285824/1/GEOTECHNICAL%20ASSESSMENT%20OF%20SUBLAKE%20SLOPES%20AND%20LIQUEFACTION.pdf
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