Opak Strike Slip Fault Modeling Interpretation Using Photogrammetry Method of Drone Survey in Trimulyo, Bantul, Yogyakarta Province

Abstract

The Opak fault was known as the Epicenter of the Yogyakarta earthquake on May 27, 2006. This earthquake claimed more than 5,000 more lives, especially in the Yogyakarta area and its surroundings. Various studies have been carried out in determining and defining Opak faults. This study focuses on describing the crush zone of the Opak fault in Trimulyo, Bantul, Yogyakarta using photogrammetry method of drone survey. The area photogrammetry of study area equal to +256.000 m2 with 231.159 tie points, 29.484.107 points of dense cloud, 1.965.606 face of 3D model, 3.08 cm/pixel resolution of the tiled model, and 12.3 cm/pixel resolution of the DEM/DTM model. The interpretation showed in this area were found in the form of two (2) major strike – slip fault that are defined as Opak Fault [4]. Opak faults are the main structure controlling this study area that have direction from 0° to 35°. There are minor faults (flower structure) with a very heterogeneous direction orientation from 0° to 160° as result of compressional wrenching from major fault, defined as number 1-10 fault. According to Sanderson and Manchini (1984) [27] model, the geometry and kinematics of structures expected for this study area are controlled by a maximum compression (σ1) axis in an approximately North-South direction, as the movement of the Indo-Australia subduction to Eurasia (South East Asia) tectonic plate [28]. This flower structure character in this area defined as the destruction zone caused the devastation in the Yogyakarta earthquake in 2006.