The Gorontalo fault zone is an active fault that crosses Gorontalo Province with a movement of about 11 mm/year. The existence of this fault zone affects the morphological lineaments and offsets along its path and increases the potential of geological disaster hazards. The Olele area is located in the Gorontalo fault zone that makes it potential to landslide disaster. This study aims to analyze the lineaments of the Olele area and its surroundings. The results of this analysis will help to determine the geological structures distribution pattern that develops in the study area and its impact on the mitigation of landslide disasters in the study area. This study uses a spatial analysis method using Digital Elevation Model (DEM) image to analyze slope and lineaments data in the study area. The results of the analysis will be correlated with regional geological structures and give recommendations for geological disaster mitigation that can be implemented. The results showed that the slope class in the study area was dominated by the range of 16-35° and even in several places with a slope of 35-55°. The results of the extraction and processing of lineaments data get 203 data. The lineaments direction is relatively NNW - SSE. This direction indicates that mostly the morphologies are influenced by the existence of the Gorontalo fault zone. The existence of the Gorontalo fault zone makes this area prone to landslide disasters in the case of Gorontalo fault movement. Some prevention recommendations are to increase the slope stability level.

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Bone River Estuary acts as a connecting lane between the three rivers (Bolango River, Bone River, and Tamalate River) with Tomini Bay. There is a port activity of goods located right on the river estuary, which is potentially disrupted due to the silting and can cause flood. This situation will undoubtedly disrupt port transportation routes and affect the economic condition of Gorontalo. The aim of this research is to identify the potential of sediment utilization at the downstream of the Bone River as an effort to prevent siltation at the estuary of river Bone, Gorontalo and to prevent flood. The method used in this research is field observation which includes observation of the morphological condition of research location and sampling. Samples will then be processed by means of sieving, separation, and classification of Sphericity sediment material by referring to zoning classification and Sneed and Folk classification. The result of histogram data showed that the sediment material was dominated by coarse sand size and grain size distribution dominated by coarse sand with size of phi is 0, on sediment data showed generally very leptokurtic with skewed skill or highly skewed.

Gorontalo infrastructure development focus on improving transport efficiency through the development of Gorontalo Outer Ring Road (GORR). The Government has set the cost 750 billion rupiahs for GORR and planned will be completed by 2019 but constrained by landslides. This research aims to reconstruct and identify the type and mechanism of a landslide at GORR. The result of this research is landslide type and mechanism in the research area. The method used is 2-dimensional electrical resistivity sounding with Wenner-Schlumberger configuration. Landslide mechanism is analyzed based on the resistivity value table on Vingoe resistivity value supported by geological data. Based on geophysical data, subsurface conditions showed blocks of limestone with a resistivity value about 132 Ωm and marked red-purple colors. These blocks of limestone interpreted as the result of the weathering process and buried in weathered clastic limestone. Landslide movement type is sliding movement and concluded as a rockslide. There is a potential for subsurface landslide blocks occur caused by the weathering process on fractures in the research area. The future prevention steps are by increasing the surface water absorption by planting in the geotextiles or prevent water infiltration in the landslide area. In addition, manufacturing retaining wall is also required.