PENENTUAN STRUKTUR BAWAH PERMUKAAN DENGAN MENGGUNAKAN METODE SEISMIK REFRAKSI DI DESA PLERET, KECAMATAN PLERET, KABUPATEN BANTUL

Abstract

A research of refraction seismic methods in Pleret village, Pleret, Bantul District, DIY has been done on June 18 to 19, 2007 with Geometrics Model ES-3000 seismic refraction instrument with 5 geophone. This research in order to determination the sub surface structure of Pleret village in coordinate easting from 435160 UTM until 435543 UTM and northing from 9130653 UTM until 9131299 UTM. In this aquisision data, the travel time data was a distance function. Processing and interpretation data used Intercept Time method. Intercept Time method used value of intercept time concept from travel time curve. This interpretation which resulted P wave velocities and layer rocks thickness in two-lines which scattered in area of survey. The result of interpretation shows that in the survey area consist of two layers, e.i: the first layer is represent land mound with velocity of line-1 is 235.849 m/s – 446.429 m/s and velocity of line-2 is 192.306 m/s – 304.876 m/s and the thikness is in range of 3 m until 5 m. While the second layer with velocity of line-1 is 748.503 m/s – 2118.644 m/s and velocity of line-2 is 726.744 m/s – 1506.024 m/s is interpreted as clay stone layer, sand (dry, having the pass character).