Determination of bed rock depth using joint geoelectric and HVSR methods. (May 2019)

• Record Type: Journal Article
• Authors: Yuliyanto, G; Harmoko, U; Widada, S
• Is Part Of: Journal of physics. Volume 1217(2019)
• Publication Date: 2019-05
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/1217/1/012039
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: To obtain hard rock (bed rock) as the pedestal of the toll road, it had been measured of the thickness of layers of soft or weathered rock that covers the bed rock. Direct measurements carried out by drilling will require a long time and great cost. Therefore, indirect measurements were made by geophysical estimation using resistivity method and were cross-checked with the HVSR method. To get the resistivity data in the research area, in this survey was conducted geoelectric sounding acquisition as much as 16 points whereas data acquisition by using microtremor measurements performed at nine measurement points. The result of the analysis of geoelectric data with HVSR data gives slightly different layer thickness value. The survey area consists of two layers of soil with soft rock layers one were suspected to be sandy silt, and silty sand whereas the soft layer 2 was sandy gravel silt, each with varying thickness. The bed rock in this area is breccia that applies as half space with the thickness is not detected by the measurement. The apparent resistivity curves were obtained from geo-electrical resistivity data have similar curves with the HVSR ones. From the inversion, the result of the bedrock depth from geo-electric resistivity compared to HVSR ones give difference slightly.