Prosiding Nasional Rekayasa Teknologi Industri dan Informasi XV Tahun 2020 (ReTII) Oktober 2020, pp. 239~246 ISSN: 1907-5995  239 Prosiding homepage: https://journal.itny.ac.id/index.php/ReTII/ Seismic Site Response Simulation of Jakarta subsoils due to 5.4 MW Banten Earthquake on July 7 th 2020 Muhammad Fatih Qodri 1 1 Jurusan Teknik Geologi, Institut Teknologi Nasional Yogyakarta Korespondensi : fatihqodri@itny.ac.id ABSTRAK Potensi kerusakan akibat gempa bumi jarak jauh dapat menimbulkan amplifikasi getaran selama perambatan gelombang. Pada tanggal 7 Juli 2020, gempa 5.4 MW terjadi di Provinsi Banten yang berfiliasi dengan aktifitas intraslab dimana Lempeng Indo-Australia yang menunjam di bawah Lempeng Eurasia. Pusat gempa relatif jauh dari pusat kota Jakarta, yaitu sekitar 95 km. Namun, sebagian warga Jakarta sempat merasakan guncangan saat gempa. Hal tersebut menunjukkan bahwa guncangan dalam jangka waktu lama bisa saja terjadi pada saat gempa. Sejalan dengan fenomena tersebut, penelitian ini bertujuan untuk menginterpretasikan efek amplifikasi yang terjadi Jakarta. Model Next Generation Attenuation (NGA) diimplementasikan untuk menghasilkan response tanah terhadap lokasi penelitian yang diselidiki. Simulasi respons tanah seismik nonlinier satu dimensi diaplikasikan untuk mengamati perilaku tanah dan parameter getaran tanah di Jakarta. Secara umum, hasil tersebut dapat menggambarkan efek amplifikasi pada kondisi tanah di Jakarta. Hasil tersebut juga ditujukan untuk menyadarkan masyarakat akan gempa bumi. Kata kunci: gempa bumi, amplifikasi, kecepatan gelombang geser, NGA, percepatan tanah ABSTRACT The potential descruction could be affected by long-distance earthquakes since the vibrations could appear amplification of ground shake during the wave propagation. On July 7 th 2020, the 5.4 Mw earthquake happened at Banten Province affiliated with intraslab activities where the Indo-Australian Plate is submerged beneath the Eurasian Plate. The earthquake epicenter is relatively far away from the downtown Jakarta, i.e. about 95 km. However, some people in Jakarta could feel the shaking during the earthquake. It indicates that the long- period shaking could happen during the earthquake. Futhermore, this study aims to interpret the amplification effect in Jakarta. The next generation attenuation (NGA) model is implemented to generate the ground motion for the investigated sites. Simulation of nonlinear one-dimensional seismic site response is then performed to observe the soil behavior and ground motion parameters on the investigated sites. In general, the results could describe the amplification effect on Jakarta subsoils. The results are also addressed to make the awareness of the earthquakes for people of Jakarta and Indonesia in general. Keyword : earthquake, amplification, shear wave velocity, NGA, Peak Ground Acceleration 1. INTRODUCTION Jakarta as the capital city of Indonesia treaten by routine tectonic activity in the surounded area of Jakarta. Meteorological, Climatological, and Geophysical Agency (BMKG) reported mild seismicity affecting Jakarta. Several earthquakes could be felt in Jakarta even though the earthquake's epicenter lies hundreds of kilometers away, such as the 5.4 Mw Banten earthquake on July 7th 2020. This earthquake has epicenter about 95 km from downtown in Banten Province. The issue that becomes a concern because Banten is relatively close to Jakarta. Seismic activity in Jakarta is influenced by the Sunda Arc subduction zone and the shallow crustal fault zone. There are 3 major faults around the city of Jakarta, namely the Semangko fault, the Cimandiri fault, and the Lembang fault (Irsyam, et al., 2017). Subsurface investigations were conducted using geophysical and geotechnical methods (e.g. seismic refraction, seismic downhole test, standard penetration test (SPT)), but these are difficult to undertake in urban areas, particularly for deep layers. The microtremor array method by Ridwan et al. (2013) was applied in this study to obtain subsurface shear wave velocity profiles underneath Jakarta. This method has been used widely, not only for scientific but also for engineering purposes, owing to its simplicity of operation and the fact that it does not require an active source. According to National Earthquake Hazard Reduction Program (NEHRP) (1998), the local site classification of Jakarta by microtremor measurement by Ridwan et al. (2013) research, concluded that Jakarta was classified as NEHRP Site Class D and E generally. The study points are shown in Figure.1. Four location are selected such as Ancol (ANCL) that is one of the tourism place in the North of Jakarta, Istana Negara (ISTN) that is the presidential palace, Kuningan