Magnetic Source of Kawah Ijen and Subsurface Magnetic Source of Kawah Ijen and Subsurface Delineation from Magnetic Data

A ground magnetic survey was conducted at Ijen caldera complex. The Ijen caldera complex hosts a large number of volcanic edifices which consists of twelve cinder cones. The youngest of these cinder cones is Kawah Ijen volcano. Magnetic survey is used to delineate the subsurface structures and to estimate the magnetic sources depth of the selected area. Edge enhancement using total horizontal derivative is mainly used to delineate the subsurface structures while the 3D Euler deconvolution is used not only to delineate major subsurface structures but also to determine the structural indices of them as well as the depth of the magnetic sources. The calculated structural indices show that the area is mainly affected by source which interpreted to be related to fault and contact/ thin sheet. Estimated source location shows that source beneath Kawah Ijen are connected to Jampit, Rantih and Merapi as rim volcanoes. Edge enhancement using total horizontal derivative represent the delineation of subsurface structure trending southwest - northeast, coincide with the fault orientation of survey area based on geological map.