Bengkulu city is well-known as a high-risk area for an earthquake. One of the effects of the earthquake is liquefaction, the phenomenon in which the strength and stiffness of the soil are reduced by shock. The researchers measured the quantity of liquefaction by knowing the value of Vs30 values that can be obtained from the United States Geological Survey (USGS). In this study, however, we measured liquefaction based on the shear strain value (γ). Here, the shear strain values could be determined by measuring the seismic vulnerability index and the peak ground acceleration. The vulnerability index was obtained by measuring the resonance of the frequency and the amplification factor using a short period seismometer with 3 components (2 horizontal components and 1 vertical component), whereas the peak ground acceleration was obtained from the earthquake data that happened in Bengkulu City in 2000. The result showed that Vs30 and shear strain negatively correlated.

Kepahiang regency is an area above the Musi segment of the Sumatran fault system. This condition makes the study area prone to natural disasters such as landslides in the slope area caused by earthquakes due to tectonic plate movement. The objective of this study was to locate potential landslide areas in earthquake-prone areas of Kepahiang regency, Bengkulu province, Indonesia. We performed horizontal to vertical spectral ratio (HVSR) analysis and simple additive weighting (SAW) methods to accomplish the goal. The acquisition of field data involved a broad band seismometer PASI Gemini-2 (triaxial geophone). The microtremor data recorded in the field were then analyzed by the wave spectrum. The results showed that the landslide potential in the study area could be divided into three categories, i.e., low, medium, and high potential. Areas with high potential should be more aware of the threat of landslides, especially in population-dense areas. The greatest threat in the study area is an earthquake along Sumatra's active fault. An earthquake that occurs in a very steep, landslide-prone area can increase risk and trigger a landslide.

Bengkulu Province is the converging path region between the Indo-Australian − Eurasian tectonic plates in the ocean and the Sumatran fault crossing on the mainland. The condition implies that the sliding force of the slab is easy to trigger fractures and to cause the material to be relatively less elastic, resulting in high seismic intensity. This study aims to identify areas with the potential for landslides and its mapping, and to analyze the factors that cause landslides in Central Bengkulu Regency, Bengkulu Province, Indonesia. This study was conducted using rock physical parameters of ground shear strain (GSS) which were correlated with parameters of slope, slope height, Vs 30 value, fault distance to measurement point, rock conditions, rainfall, and PGA value. Furthermore, these parameters were overlaid thoroughly by the statistical method of the Analytical Hierarchy Process (AHP). Data acquisition is divided into two stages, namely the secondary data collection stage and the field survey stage. Secondary data collection was carried out to support the creation of landslide potential maps, analysis, and field survey data input. Secondary data is the value of Vs 30 , the distance of the fault to the measurement point, rainfall, and the PGA value. Field survey data are in the form of GSS values, slope, slope height, and rock conditions. The results of this study are identified areas that have the category of high, medium, and low landslide potential. Based on the calculated parameters, the GSS parameter is the most dominant which affects the landslide potential in the studied area.

<p class="AbstractText">Bengkulu City is located in the subduction zone of the Indo-Australian and Eurasian plates, so it is prone to earthquake. To anticipate the impact of earthquake, disaster mitigation can be carried out, one of which is a study of the level of rock hardness in the area. This study aims to determine the level of rock hardness based on seismic wave velocity in several rock formations and to determine which rock formations have the potential to cause vulnerability to earthquakes. Field data acquisition uses the seismic refraction method with time-term inversion technique. The data obtained in the field are processed to obtain a 2-D cross-section of the subsurface seismic wave velocity values. The study results show that the level of rock hardness depends on the type of rock formation. The Andesite Rock Formation Unit (Tpan) has the highest level of hardness, while the transitional area between the Alluvium Rock Formation Unit (Qa) and the Swamp Sedimentary Rock Formation Unit (Qs) has the lowest level of hardness.</p>

ABSTRAK-Kota Bengkulu merupakan daerah yang sangat rawan terhadap ancaman gempabumi. Salah satu upaya mengurangi dampak bencana gempabumi adalah melakukan analisis potensi tersebut berdasarkan data mikrotremor dan metode pembobotan statistik. Penelitian ini bertujuan memetakan dan menganalisis daerah-daerah yang rentan mengalami ancaman bahaya gempabumi. Penelitian ini dilakukan menggunakan data sekunder dan survei lapangan. Data sekunder bersumber dari penelitian-penelitian terkait, sedangkan data survei lapangan berupa data mikrotremor menggunakan metode Horizontal to Vertical Spectral Ratio (HVSR). Alat yang digunakan untuk survei lapangan berupa broadband seismometer PASI Gemini-2 triaxial geophone dengan natural freq. 2 Hz ± 10%, berat 2 kg (s.n.: 12/004). Akusisi data lapangan dilakukan selama 30 menit (360.000 samples) per titik pengukuran dengan sampling rate 5 ms (200 Hz). Selanjutnya, tumpangsusun hasil pengolahan data sekunder dan lapangan menggunakan metode pembobotan statistik Analytical Hierarchy Process (AHP), sehingga diperoleh peta potensi kerentanan gempabumi di wilayah studi. Berdasarkan hasil analisis yang ditunjukkan dalam peta kerentanan gempabumi di daerah Kota Bengkulu dalam penelitian ini, Kecamatan Gading Cempaka, Kecamatan Singaranpati, Kecamatan Selebar, sebagian kecil Kecamatan Ratu Agung, dan Kecamatan Muara Bangkahulu adalah daerah yang mempunyai potensi kegempaan tinggi, sedangkan Kecamatan Selebar adalah daerah yang mempunyai potensi kegempaan rendah. Oleh karena itu untuk daerah berisiko tinggi perlu lebih diwaspadai dan perlu perencanaan pembangunan yang mengacu kepada standar risiko bencana.

Bengkulu Province, due to be crossed by Bukit Barisan Mountains has relatively large geothermal reserves. This study aims to investigate the geothermal reserves in Babakan Bogor Village, Kepahiang Regency, Bengkulu Province. The magnetotelluric (MT) method with electric and magnetic sensors was used to record data in the fields. The electric sensor consisted of three porous pots, two of which were placed horizontally (Ex, Ey) and the other one vertically (Ez) as the ground. Magnetic sensors with two coils were placed horizontally (Hx, Hy) and one vertically (Hz). The data obtained in the field are in the form of rock resistivity values which are correlated with geothermal potential, so that the reservoir could be determined. Data recording in the fields used low frequencies, i.e. 128 Hz. Data processing was done using MAPROS software to convert time-series data to EDI file types. Input data in the MAPROS software is in the form of apparent resistivity vs. depth values. Furthermore, an inversion was carried out to obtain the true resistivity value as the output of the software. ZONDMT1 and ZONDMT2 were used to model the resistivity values in one dimension (1D) and two dimensions (2D). The results showed that there were geothermal reserves in the Babakan Bogor Village, Kepahiang Regency, at a depth of 1,500 to 5,000 m.

The thickness of the weathered layer in the landslide zone can be determined by the seismic refraction method. This study aims to determine the thickness of the weathered layer based on the primary wave velocity (P-wave or Vp ). Data acquisition is taken around the landslide zone, namely above the landslide, parallel to the landslide, and perpendicular to the landslide. The data were collected using a digital seismograph 16S24. Furthermore, the data obtained in the field is processed to obtain a 2-D model. The results showed that the thickness of the weathered layer above the landslide was 2.15 m - 4.59 m with a Vp value equal to 185 m / s. For the thickness of the weathered layer parallel to landslides is 0.80 m - 4.11 m with a Vp value equal to 300 m / s and the thickness of the weathered layer perpendicular to landslides is 0.01 m - 2.35 m with a Vp value equal to 300 m / s. Meanwhile, the bedrock layer under the weathered layer has Vp of between 517 m / s to 1065 m / s in the form of sub-consolidated clay to very dense clay lithology.

Bengkulu city is facing groundwater problems where some of the groundwater is brackish. The study aimed to determine the structure of the subsurface layer through the propagation velocity of secondary wave (Vs) in a layer of porous medium in estimating the potential for groundwater. This research supported by resistivity data ​​and will be validated based on the depth of the well. MASW data was processed using WinMASW Professional 5.0 software to obtain a 1D profile of the Vs value, and Res2dinv software was used to obtain a 2D cross-section of the resistivity value. The results showed a decrease in the value of Vs in the porous medium layer from 133 to 358 m/s in the first path, and from 149 to 314 m/s for the second path. The decrease in the value of Vs is in the range of groundwater potential which is close to the depth of the resident's well, with the type of porous medium layer being sands and intact clays. The subsurface profile from the Vs measurement shows a good agreement with the resistivity value profile from the Geoelectric method. So, secondary wave propagation can be used in determining groundwater potential for a depth of < 10 m