The acquisition of seismic reflection involves generating and recording seismic wave field on/near the surface of the earth. Success of producing high quality seismic data depend on choice of seismic sources. There are commonly seismic sources for land seismic surveys such as explosive sources, vibrators and Accelerated Weight Drop (AWD). In some cases, the use of explosive sources often faces many problems, especially related to the costs, permission and environmental issues. The use of vibrators is also similar, facing problems such as the availability of access roads, permits and the environment impact. The use of AWD seems to be a solution as an alternative seismic sources when explosive or vibroseis cannot be used for some reasons. In this research, we have designed and built a mechanical seismic source named AWD250V1.0. This hand-made AWD prototype was developed for shallow seismic surveys. To evaluate the performance of this tool and to improve the design of the prototype, a field tests have been carried out. The test was conducted in Ciparay village, Bandung Regency, West Java. The survey area is mostly paddy field with the near surface covered by clay and highly seismic attenuation. The purposes is simply whether AWD can work properly or not while maintaining data quality and safety standards. In addition, the test is intended to find out how deep penetration of seismic waves using this source. Seismic recorders used were 96 channels with interval between receivers was 10 meters. Findings showed that the deepest reflection can be seen around 450 millisecond or approximately 400 meters. To sum up, the device is work well and is able to produce good quality of seismic sources. The prototype can also meet design criteria that are repeatability, portability, economical and environmetal friendly.
All geophysical techniques are depends on the existance of a contrasts in physical properties of materials. Since the complexity of the subsurface physical properties can vary, the knowledge of basic theories about it should be validated with practical skills. One effective way to improve the practical skills is by designing a small-scale instrument of well logging to identify the resistivity of the subsurface layers. In this research, a simple tunnel model is implemented in order to represent a complex geological model. Based on well-logging principles, this prototype is made to identify variations in resistivity value using a logger equipped with Wenner Array of four electrodes. An Arduino UNO microcontroller is utilized to arrange the work of the logger and programmed to process the potential values. It is obtained from the electrodes and displayed by the interface. In order to test the propotype, the air-filled tunnel models are performed. At the location near the air-filled tunnel, the resistivity log data give highest values compare any other location due to the air material. The results show that the resistivity well logging data are able to represent the air-filled tunnel model. The 3D model of well log data can identify the type of the physical properties of material in the air-filled tunnel model. Furthermore, the simple concept of this prototype can be developed for large-scale utilization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.