Central Java Southern part area deformation analysis by using GPS-CORS 2015

Abstract

Indonesia located on the convergence area of four active tectonic plates. Eurasia plate collides with Indo-Australia plate which forms subduction zone at the south of Java Island and forms the java island. Indo-Australia plate moving north by 7cm/year subducting under tectonic plate of Eurasia that relatively stated. As the results, tectonics and volcanic earthquakes are commonly occured at the boundary. In 2006, 5.9 Richter’s scale earthquake, took place in Jogjakarta its surrounding, causing severe damage to the infrastructures. Therefore, Central Java has been marked as the seventh area which has high possibilities of earthquake in Indonesia. The aim of this research is to investigate deformation that happened at the South of Central Java using data of Continously Operating Reference Station of Indonesia (Ina-CORS) from 2013-2015. The deformation result is represented in the form of vectors and shifting velocity. Based on the result, it can be analysed that all six stations observed have the similar moving direction that is to the southeast with the horisontal velocity valued from 0.00910 to 0.01203 m/year. The vertical velocity of six stasions range from −0.01147 to 0.04354 m/year. From strain calculation using triangle segment it is found thet the value of compression bigger than extention value. Dominant extention value is in CSLO-CMGL-CBTL segment. The Value ε1: 0.01879 μstrain and ε2: −0.00997μstrain