General geology in Lakota, Jeli, Kelantan and seismic refraction analysis in polytechnic of Jeli, Jeli, Kelantan

Polytechnic of Jeli is located in the Lakota area about 90 kilometers from Kota Bharu , the main city of Kelantan state. The seismic refraction analysis is a part of final year project of student that decided to find the layers of rock beneath the surface of the study area. The decision was made to use this type of geophysical method because the cost was lesser compared to other geophysical method. The complicated physical setting of the study area made the planning of the seismic refraction survey was important and crucial. The bedrock surface at the site was quite irregular. dominantly by mafic rocks and has foliation and joints at the surface of the rock. The outcrop of rock was elongated down toward the PETRONAS's store room. Therefore, we decided to shoot four lines of shots, which were three was parallel each other and one line was across those three lines. Field work of geological mapping was done started from May until October of 2013 and seismic refraction investigation was done June 7 2013. We obtained coverage of total of four line about 400 meters long spreads along the field of study area. The source of the wave was directly from the sledgehammer slammed on the iron plate that generated by human. To avoid overwhelming background noise from the outside sources that become unnecessary to the reading of seismograph. The example of background noise happened on that investigation was the vehicle movement and human activity. We performed the investigation early in the morning when the traffic and human activity was in low rate. Survey results showed not only in highly irregular bedrock, weathered and sheared bedrock surface, but also indicated variations between the soil, weathered rock and bedrock in term of margins of the layers. The method was used was generalized reciprocal method (GRM) that proved most suitable for situations involving velocity variations and highly irregular reflector surfaces. To obtain the truth of this survey, the boring should be done in this area at least seven boring along those four lines. The Polytechnic of Jeli study shows the importance of planning of the survey with the physical and geological characteristic of study area and the objectives of the survey in mind. It also shows the flexibility, the correctness and the reliability of GRM method at a lower cost than drilling method alone.