Peta Respons Spektrum Provinsi Sumatera Barat untuk Perencanaan Bangunan Gedung Tahan Gempa
DOI:
https://doi.org/10.5614/jts.2009.16.2.3Keywords:
Teori probabilitas total, Respons spektra.Abstract
Abstrak. Gempa aceh pada bulan Desember 2004 silam telah membuktikan zona sumber gempa subduksi Sumatera mampu menghasilkan magnitude Mw9,0 yang hampir setara dengan kejadian gempa pada zona subduksi di sekitar kepulauan Mentawai pada tahun 1883. Berdasarkan pertimbangan itu, dilakukan studi analisis hazard kegempaan pada wilayah Provinsi Sumatera Barat berdasarkan kriteria desain yang disyaratkan dalam SNI-1726-2002, yaitu untuk umur bangunan 50 tahun dan nilai kemungkinan terlampaui 10%. Analisa tersebut dilakukan berdasarkan teori probabilitas total dengan memanfaatkan perangkat lunak EQRISK yang dimodifikasi dan menggunakan pemodelan sumber gempa 2-D berdasarkan kajian seismotektonik dan identifikasi regional fault. Respons spektra desain di permukaan tanah diperkirakan berdasarkan faktor amplifikasi yang mengacu pada NEHRP 1997 berdasarkan spektra percepatan di batuan dasar untuk periode 0,2 detik dan 1,0 detik. Hasil akhir yang diperoleh adalah peta spektral percepatan pada lapisan batuan dasar di wilayah Provinsi Sumatera Barat dan respons spekra desain permukaan tanah dengan periode ulang 500 tahun.Abstract. The big earthquake event acted in Desember, 2004, shows that the subduction zone of the Sumatran trench is able to produce the magnitude 9,0 which is almost equal with the magnitude of the big earthquake event on Mentawai island in 1883. Therefore, a seismic hazard analysis was conducted on area of province West Sumatera to evaluate the significant code which develops based on SNI-1726-2002, that implements spectral hazard for 10 % probability of exceedance in building life time period of 50 years. The analyses were carried out using 2-D earthquake source model and the seismic hazard analysis software named EQRISK that is based on the total probability theorm. The design response spectrum on site ground surface are approximated by the amplification factor of NEHRP 1997 codes on spectral periods of 0,2 second and 1,0 second. The final result of this study are the spectral acceleration maps on the bedrock of province West Sumatera, and the design response spectrum on site ground surface for return period of 500 years.
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