Sumatra Barat memiliki tingkat kegempaan cukup tinggi karena berada pada zona Megathrust, Sesar Mentawai, dan Sesar Sumatra. Tingginya tingkat kegempaan ini mempengaruhi nilai percepatan tanah di Sumatra Barat yang merupakan parameter penting dalam perencanaan bangunan tahan gempa. Metode Gutenberg-Richter merupakan salah satu metode empiris untuk menghitung nilai percepatan tanah maksimum (PGA) dan intensitas gempa bumi berdasarkan magnitudo gempa. Data penelitian ialah data katalog gempa bumi dari BMKG dan USGS dengan periode 01 Januari 2005 hingga 15 September 2020 dengan magnitudo gempa Mb ≥3 dan kedalaman ≤70 km. Berdasarkan data BMKG diperoleh gempa bumi sebanyak 1136 kejadian dan menunjukkan nilai PGA di Sumatra Barat sekitar 0,16 – 1,44 m/s2 dengan intensitas V–VIII MMI serta episenter menyebar di zona akresi, zona Sesar Sumatra dan zona Sesar Mentawai. Sedangkan dari USGS diperoleh gempa bumi sebanyak 1140 kejadian dan menunjukkan nilai 0,28 – 1,35 m/s2 dengan intensitas VI–VIII MMI serta episenter yang menyebar di zona Sesar Mentawai. Berdasarkan analisis data baik dari BMKG maupun USGS diperoleh bahwa Kabupaten Kepulauan Mentawai adalah wilayah yang memiliki tingkat risiko gempa bumi paling tinggi dan berpotensi tsunami dengan nilai percepatan tanah maksimum sekitar 1,29 – 1,44 m/s2 dengan intensitas VIII MMI.

The purpose of this study was to determine how the tsunami disaster zoning in the Regency and Coastal City of West Sumatra Province was determined. The survey results show that geographically the regencies and cities on the coast of West Sumatra are around the threat of a tsunami, in addition to economic activities, government activities, and high population density around the coastal area. Regencies and cities located on the coast of West Sumatra, including West Pasaman Regency, Agam Regency, Padang Pariaman Regency, Pariaman City, Padang City, Pesisir Selatan Regency, and the Mentawai Islands, are feared to be the following places to be hit by a tsunami, for this reason, efforts are needed - efforts to overcome the tsunami hazard. In conclusion, the tsunami risk zone in the province of West Sumatra, which is very dangerous, is in the Mentawai archipelago with a wave height of 20-35 m and a wave arrival time of 10-20 minutes with a warning level of alert. And the story of tsunami disaster risk in coastal districts and cities of West Sumatra province is divided into four zones, namely: Not dangerous, Less dangerous, namely West Pasaman district, the danger is Agam district, Pariaman city, Padang Pariaman district, Padang city, and Pesisir Selatan district, Very dangerous namely the Mentawai Islands.   Keywords: ArcGis 10.3, Comcot, Tsunami

Desa Jati Mulyo berada di Kecamatan Dendang Kabupaten Tanjung Jabung Timur yang didominasi oleh gambut sehingga rentan terhadap penurunan muka tanah. Penelitian ini bertujuan untuk mengetahui tingkat kerentanan tanah serta distribusi nilai parameter mikrotremor. Pengukuran dilakukan menggunakan seismograf MAE A6000S sebanyak 36 titik yang tersebar di Desa Jati Mulyo. Analisis data mikrotremor menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) dengan menggunakan perangkat lunak Geopsy menghasilkan nilai parameter frekuensi alami (f0) dan amplifikasi (A0), selanjutnya perhitungan dilakukan untuk menentukan nilai indeks kerentanan seismik (Kg). Hasil penelitian menunjukkan rentang nilai frekuensi natural area penelitian berkisar antara 0,57 Hz hingga 9,12 Hz. Kemudian nilai faktor amplifikasi berada diantara rentang 1,87 hingga 7,54 dan nilai indeks kerentanan sesimik berada diantara rentang 0,80 hingga 33,44. Berdasarkan Hasil Penelitian, terdapat 3 zona kerentanan seismik pada daerah penelitian, yaitu zona rendah, zona sedang dan zona tinggi. Daerah penelitian di dominasi oleh zona tinggi yang mana hampir seluruhnya tersebar di kawasan penelitian. Hal ini dikarenakan wilayah penelitian merupakan endapan aluvial yang tertutup lahan gambut, maka terdapat bahaya penurunan muka tanah yang tinggi dan dan berpotensi terjadi kerusakan akibat gempabumi.

Assessment of seismic hazard is necessary in land use planning and hazard mitigation. It leading to subdivided a region into sub-region which different safeguards to prevent damage in case an earthquake is occurred. The quantitative assessment of seismic hazard is carried out in Sungai Penuh and Kerinci Regency using deterministic seismic hazard analysis (DSHA) method. Earthquake scenario of Mw 7 at depth of 10 km by Siulak fault source were used for analysis to estimate the ground motion over the investigated areas. The resulting DSHA map reveals high seismic hazard level in terms of PGA 49.8 – 71.9 gal alongside the active Siulak fault zones. The intensity of the region are dominated by VII-VII of MMI scale which puts in the high hazard zone.

Jambi is an area that has natural resources in the form of petroleum, one of which is the Bajubang region. Bajubang is located in the Jambi Sub Basin where ripe hydrocarbons are visible in the Talang Akar Formation. Petroleum exploration continues to run out of oil reserves. To find the presence of a sedimentary basin that has stopped, it can be done by measuring the gravity method. The basic concept of this method is to measure the geographical variation of an area on the earth's surface and corrected through the prevailing measurements or prices. The purpose of this research is to determine the geological structure pattern that causes the formation of sub-basins that indicate the presence of hydrocarbons and describe the subsurface conditions using forward modeling and backward modeling. Based on the modeling results found as many as 7 sub basins sediment. The height and fault structures are identified in the subsurface model. Based on the regional anomaly map shows the presence between the basin and the elevation. The fault structure, anticline and sub-basins are found which are expected to produce hydrocarbons.