Identify activated fracture area using HC-plot methode in Sulawesi region

Abstract

The tectonic condition of the Sulawesi Island is formed as a result of convergent and transform motion. Earthquake event with magnitude M 7.0 in Sulawesi region rarely happen, only earthquake with magnitude above M 5.0 which often. Required more identification of fracture plane of earthquakes with magnitude above M 5.0. The object of this study is to identify the area of activated fracture in the Sulawesi region from the earthquake focal mechanism data. Determination of activated fracture plane using HC-plot method, that is determination method of hypocenter location estimation to centroid. Using earthquake catalog data from BMKG, USGS, and GFZ. The earthquake data which used in this methode is data with magnitude M> 5.0 span of time in 2016 in Sulawesi region. The parameters which used in this study are hypocenter, centroid, dip and strike of each earthquake. The centroid, dip and strike parameters are obtained from Global CMT seismic network. The number of earthquake with magnitude more than 5.0 as much as 4 events are Gorontalo earthquake M 5.4, Bolangmongondo earthquake M 5.1, Palu earthquake M 5.3, and Bitung earthquake M 5.8. From the result of data processing obtained by distance of hypocenter to centroid every quake respectively from 14.23 km, 17.65 km, 4.48 km, and 24.34 km. In addition to the distance of the hypocenter to centroid also obtained a distance hypocenter to nodal plane 1 and nodal plane 2. The distance from hypocenter to nodal plane 1 each earthquake in a row is 3.09 km, 10.79 km, 3.53 km, and 16.02 km. Same as for the hyposenter distance to the nodal plane 2 of each quake respectively is 6.92 km, 6.97 km, 3.58 km, and 15.60 km. Comparison using three catalogs indicate that the hypochenter distance that almost coincides in one of the nodal planes is the fractured plane activated during an earthquake.