The Tehoru earthquake occurred due to the release of stress in rocks. There is a release of energy as an earthquake as a result of the rock elasticity limit has been exceeded because the rock is no longer able to withstand the stress. One method to determine the distribution of earthquake stress is the Coulomb stress change method. The study aimed to determine the DCS of the Tehoru earthquake, Seram Island, and the effect of the main earthquake stress release on aftershocks.  The research results show that the DCS distribution of the Tehoru June 16, 2021 earthquake is shown with negative lobes and positive lobes. The negative lobe is found in an area that is perpendicular to the fault plane and has been identified as having experienced relaxation, so there may be still aftershocks with stress values ranging from (0.0 – 0.3) bar. The dominant positive lobe occurs next to the southern end of the fault plane, too much located in the area of increasing Coulomb stress with values ranging from (0.2 - 0.6) bar

Kegagalan lereng yang terjadi pada suatu lereng memiliki bidang gelincir pada struktur bawah permukaan sehingga dapat menimbulkan bencana longsor. Bencana ini terjadi di lokasi penelitian karena berada disekitar jalur patahan sehingga sebagian tanah mengalami retak dan longsor. Bencana ini disebabkan oleh hujan dengan durasi beberapa jam dan berada di jalur patahan, sehingga tanah menjadi jenuh dan terlepas menggelincir mengikuti lereng dengan kecepatan yang tinggi dan panjang larian yang semakin jauh sampai mengendap. Hal inilah yang menyebabkan kerusakan dan kerugian, korban jiwa, pengungsian dan kerusakan lingkungan. Penelitian ini dilakukan di longsor Booi untuk menjelaskan perumusan model fisika dalam menentukan kecepatan dan panjang larian longsor menggunakan hukum kesetimbangan energi mekanik berdasarkan pada model lumped mass. Hasil analisis memberikan estimasi kecepatan maksimum 13.3 m/s di posisi 33.0 m berada pada elevasi 96.2 m.dpl dan panjang larian longsor 102.2 m. Model profil estimasi kecepatan terhadap panjang larian longsor Booi menyerupai profil kecepatan longsor Elm. Dengan demikian, semakin besar sudut kemiringan lereng terhadap sudut gesekan maka kecepatan longsor semakin tinggi dan panjang larian semakin besar. Alterasi kecepatan longsor sangat tergantung pada elevasi lereng dan jangkauan pengendapan material longsor. Kata Kunci: energi mekanik, estimasi kecepatan, longsor elm, panjang larian

At the time of entering the rainy season from year to year in the Maluku region, especially the Ambon Island area experienced an increase in landslides due to rainfall, human activities such as excavation under the slopes, loss of vegetation, changes in land use and so on. The disaster that occurred on RT.03 / RW.01 Batu Gadjah Village, Sirimau Subdistrict, Ambon City, on June 1, 2018, ago, still leaves a trace of damage that until now. In this study, the researcher will analyze the slope (deformation that occurs) in the 2D model using Finite Element Method (FEM), by reviewing the weathering conditions of the rocks that are read from the results of the drill data in the form of soil properties and variations in rising groundwater levels. The results of calculations using FEM on dry slope conditions obtained the value of safety factor (FS) 1.10 and the analytical of FS value 1.18. This FS value indicates that the study area is still prone to landslides. Then the calculation with FEM on the wet slope conditions by rainwater obtained an FS value of 0.90, and analytically the FS value of 0.99. This FS value indicates that the research area has experienced a landslide.

To reduce the risk of landslides and to be aware of areas that have the potential for further landslides, detailed measurements of these zones are required. Measurements were made to identify a sliding plane below the surface using the geoelectric resistivity method of the Wenner-Schlumberger configuration. The resistivity data from the interpretation results are used to determine slip plane’s slope and the potential for landslide masses. The research location is on steep hills in Air Kuning Batu Merah, Ambon City. The results showed that the slope angles for line-1 were 4.20 degrees, line-2 was 17.60 degrees, line-3 ranged from (22.80 - 23.20) degrees, and line-4 was 21.80 degrees. Furthermore, the estimated volume potential of landslide mass based on the cross-section of subsurface resistivity is 3,063.88 m3. With an indication of a landslide field, the slope has the potential for a subsequent landslide if affected by external and internal factors.

From the aspect of the earth, the Maluku islands are a unique formation. Because Maluku is at the confluence of four world plates (Indo-Australian plate, Pacific plate, Philippine sea plate and Eurasian plate) so it has an interesting geological structure. One of unique formation is having thousands of islands with charming white sand beaches. White sand beaches are part of the geotourism diversity in Maluku, so research is conducted at Latuhalat (Santai and Namalatu beaches) and Suli (Natsepa beach) which aim to identify the shape and size of beach sand, analyze mineral content using the X-RD and X-RF methods. The results showed the shape of sand grains in the Santai and Namalatu beaches of Latuhalat Village were identified as oval-shaped irregularly with an average size of Santai sand grains of 0.12 mm and Namalatu sand of 0.21 mm. While the shape of sand grains in Natsepa beach, Suli Village was identified as spherical with an average grain size of 0.10 mm. Beaches in the three locations are classified as types of sandy beaches (sand sediments) with sandstone rock types. Sand on the Namalatu beach, Santai beach, and Natsepa beach has very fine to medium grain size andcontains Aragonite (CaCO3) and Quartz (SiO2) minerals that are dominant. The shape and size of the grains of sand and its constituent minerals are very good to support the Namalatu and Santai beach geotourism in Latuhalat Village and Natsepa beach in Suli Village.