PROBABILISTIC LIQUEFACTION POTENTIAL ANALYSIS OF SAN FERNANDO PAMPANGA, PHILIPPINES USING SEMI-MARKOV CHAIN

Abstract Sulawesi Island has a Palu Koro Fault that actively moves with a high displacement magnitude but low seismicity. On 28 September 2018, at 18:02 local time, an earthquake occurred in Palu Koro Shear Fault. The field investigations along the Palu coast revealed new evidence regarding the extensive liquefaction in these areas, both inland and coastal land. The research command area was located in the Palu Bay coastal area, the Province of Central Sulawesi. The data used was in the form of the Standard Penetration Test of the area, and the potential liquefaction analysis was carried out using the simplified procedure method. Furthermore, to determine the level of liquefaction potential, Liquefaction Potential Index was applied. Geological observations showed that the soil condition in the Palu Bay area was dominated by non-cohesive soil (sand). Based on the liquefaction potential analysis, it was indicated that most of the eastern region of the Palu Bay area showed no liquefaction potential. On the contrary, the western and southern parts were indicated to have liquefaction potentials. The Liquefaction Potential Index analysis results showed that the western and southern areas were dominated with extremely high liquefaction potentials. Meanwhile, in the eastern area, it was extremely low.

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Analisis Potensi Likuifaksi dengan Metode Deterministik di Wilayah Surabaya

Reka Buana Jurnal Ilmiah Teknik Sipil dan Teknik Kimia ◽

10.33366/rekabuana.v4i1.1195 ◽

2019 ◽

Vol 4 (1) ◽

pp. 68

Author(s):

Himatul Farichah ◽

Putu Tantri Kumala Sari

Keyword(s):

Relative Density ◽

Degree Of Saturation ◽

Fine Content ◽

Alluvial Deposits ◽

Liquefaction Potential ◽

Cyclic Shear ◽

Potential Analysis ◽

Cyclic Resistance ◽

Advanced Analysis ◽

Earthquake Potential

Surabaya has an earthquake potential reach to 6.5 Mw. Moreover, on average, Surabaya area is a lowland which is alluvial deposits. Thus, it is required to perform potential liquefaction. Liquefaction potential analysis was performed by taking the soil data from the center of Surabaya. The initial of liquefaction potential analysis was conducted by considering soil gradation, relative density (DR), fine content (FC), degree of saturation (SR) dan SPT number. However, the advanced analysis was undertaken by utilizing Youd and Idriss 2001 dan metode Idriss 2008. The results of initial of liquefaction potential analysis show that the soil has potential to be liquefied at the depth 1-7m, however at the depth 22m the soil is not liquefied. Furthermore, the results of advanced analysis and conclusions of the analysis show that the soil has a liquefied potential at the depth 17 m from the surfaceABSTRAK Kota Surabaya memiliki potensi gempa yang terjadi bisa mencapai 6.5 Mw. Selain itu, Wilayah kota Surabaya merupakan daerah yang rata-rata dataran rendah, yang berkisar 80% merupakan endapan alluvial. Sehingga perlu dilakukan analisis potensi likuifaksi. Analisis potensi likuifaksi hanya dilakukan pada data tanah wilayah Surabaya Pusat. Analisis awal potensi likuifaksi dilakukan berdasarkan aspek gradasi tanah, relative density (DR), fine content (FC), derajat kejenuhan (SR), dan jumlah pukulan SPT. Sedangkan analisis lanjutan dengan menghitung Cyclic Shear Ratio (CSR), Cyclic Resistance Ratio (CRR), dan Factor of safety (FS) dengan menggunakan metode Youd dan Idriss 2001 dan metode Idriss 2008. Berdasarkan analisis awal, pada kedalaman 1-7 m masih ada potensi likuifaksi, sedangkan tidak ada lagi potensi likuifaksi pada kedalaman lebih dari 22 m. Berdasarkan analisis lanjutan dan kesimpulan analisis, hampir semua kedalaman memiliki potensi likuifaksi hingga kedalaman 17m.Kata kunci : Likuifaksi; gempa; analisis potensi likuifaksi

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