Seismotectonic study in Merangin national geopark, Jambi

The Merangin district, Jambi Province, is the national Geopark because it has unique geological diversity if compared to other areas due to the discovery of Permian rocks in Merangin district. However, the Merangin district has a high earthquake activity level. The aim of this research is to know the relationship between the geological conditions in the subsurface with earthquake activity level in the research area. The methods conducted in this research was direct measurement method in the field, in the form of geological structure mapping. The dip and strike data were then analyzed in order to know the main stress and strain of rocks. Studio analysis method was also conducted, which included three analyses. First, lineament analysis of the ridge and valley from DEM SRTM (Digital Elevation Model Shuttle Radar Topography Mission) satellite imagery. Second, the analysis of potential earthquakes using the records of past earthquakes and the geometry of the faults in the form of a seismotectonic map. Third, morphometry map analysis. The geological structure mapping in the area shows that the joint direction oriented Northeast-Southwest. Meanwhile, the analysis of geological structure through DEM SRTM and from the earthquake data displayed five earthquake epicenters with a depth of more than 100 km in the subsurface with magnitude scale 4.2-4.4 Richter Scale (RS). Thus, the earthquake which occurred in the research area were all due to the subduction zone. In the morphometric map, it shows that the geomorphology in the area of research is split into two main classifications, moderately steep in upper zone and sloping in the lower zone. In conclusion, though the Geopark Merangin has many high earthquake activity levels, but since they occur due to the subduction zone, the earthquake can be classified as a middle-scale and have less effect on the surface.