Analisis dua dimensi kestabilan Lereng Kubah gunung Merapi menggunakan paket Program Clara

Abstract

Telah dilakukan Analisis duct dimensi ke,stabilan lereng kubah lava Gunung Merapi dengan Analisis batik terhadap longsoran kubah lava 1994 meng,gunakan metoda keseinzbangan batas. Peia topograli kuhah bulan Agustus digunakan sebagai model geornetri permukaan. Longsoran kubah lidak terjadi pada lava tua sehingga kekuatan parameter hanya diperoleh dari permukaan longsoran kritis pada lava 1994. Analisis balik.terhadap longsoran kubah 1994 menzberikan perkiraan nilai sudut gesek dan kohesi yang ditunjukkan dalarn hubungan kohesi versus sudut gesek. 13erdasarkan mot:Mogi kuhah lava dari bulan Januari 1997- Mare! 1997, perbandingan b/H 0,22 clan sudut gesek 15° sehingga diperoleh nilai kohesi 535,5 k M712. Hasil Analisis dengan CLARA menztnjukkan bahiva jaktor kearnanan berkurang 0,02; 0,065 dan 0,202 untuk tinggi bidang sentuh 90 In, 120 in dan 150 yang mana volume lava bertanzbah 2.900 rr2 . Bet kurangnya faktor kearnanan pada orde 10'2 karena pertumbuhan kubah lava menyebabkan kestabilan lereng kubah terganggu sehingga lereng kubah lava dalam kondisi tidak stabil. Kata Kunci : Analisis batik, Metodu keseinzbangan haws, Faktor keamanan It had been analyzed two-dimension lava dome slope stability on Mt. Merapi with back analysis methods upon the lava dome collapse by using limit equilibrium method The dome topography map in August 1994 was used as a model the surface geometry. The dome collapse had not happened to that old lava, so the parameter strengths were only get from the critical failure surface on lava in 1994. Back analysis of the 1994 dome .collapse gave the estimate for the friction angle and cohesion, which is give by curve cohesion versus friction angle. According to the morphology lava dome from January to March 1997, the comparison of b/H is 0,22 and friction angle is 15° as will be got the cohesion value is 535,5 k N/m2. The result of the analysis with CLARA showed that the safety factor decrease 0,021; 0,065 and 0,202 far elevation of tangent plane 90 in, 120 in, 150 m, while volume of lava increase 2.900 m3. The decrease of the safto, in order 10-2 because to growth lava dome makes the lava slope stability was bothered so lava dome slope in unstably conditions. Keyword : Back analysis, Limit equilibrium method, Safety factor