Available online at: http://proceeding.rsfpress.com/index.php/ ess/index LPPM UPN “Veteran” Yogyakarta Conference Series Proceeding on Engineering and Science Series (ESS) Volume 1 Number 1 (2020): 1-11 Research Synergy Foundation DOI: https://doi.org/10.31098/ess.v1i1.152 RSF Press Integrate of Geoelectric and Geomagnetic Methods to Construct Subsurface Model as Early Landslides Mitigation in Kalirejo, Kokap, Kulonprogo Hafiz Hamdalah,Eko Wibowo Universitas Pembangunan Nasional Veteran Yogyakarta 1 Email address hafizhamdalah@upnyk.ac.id 2 Email address wibowo.ekogeofisika69@yahoo.com Abstract Kalirejo, Kokap, Kulonprogo area is part of Yogyakarta in the west which borders the Province of Central Java. In general, the geomorphology of this research area consists of hills with varying slopes ranging from 15 o - 60 o , lithology consists of massive andesite intrusion with intense weathering, this can be a mass movement. The study uses geoelectric and geomagnetic approaches to identify components that allow mass movement or landslides to occur. Based on the response of geoelectric data, it is known that andesite rocks that have impermeable properties can become a slide plane having a resistivity contrast between 100 - 3000-ohm meters. Geoelectric data also describes the presence of surface aquifers which can be an important component in landslides. The water-saturated lithology has a resistivity range of 10 - 40-ohm meters. Based on the analysis of geomagnetic data with a magnetic intensity value range ranging from -400 - 1400 nT, it is known that the research area has a fairly high structural intensity. Analysis of geoelectric data shows that the thickness of the unconsolidated sediment is thick enough and the layer underneath is an impermeable rock layer, so it can be concluded that has a high potential for landslides. Keywords: geoelectric geomagnetic, resistivity, slide plane, landslide This is an open access article under the CC–BY-NC license. I. INTRODUCTION The type of weathering soil that is often found in Indonesia is the result of volcanic eruptions. This soil has a composition of mostly shale with little sand and is fertile. Weathering soil that is on top of the impermeable rock on hills/ridges with moderate to steep slopes has the potential to cause landslides in the rainy season with a high quantity of rainfall. If the hills do not have strong and deep roots, the area is prone to landslides. One of the areas with a large potential for landslides in Yogyakarta is Kalirejo village, Kokap, Kulonprogo. especially Kalibuko 1 and Kalibuko 2 areas which are recorded to have a population of 5,639 people. Therefore, an initial step is needed in disaster mitigation by mapping and evaluating the potential for landslide disasters in the area. (Mubekti, dan Alhasanah, 2008).