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Georadar method with radar reflection profiling configuration and geoelectrical method with dipole-dipole configuration has been done to determine the lithology, fracture characteristics of weak zone or fault that could potentially result of mass movement in Liwa, Lampung Barat. This research was conducted in 11 lines. Reflexwave software has been used in georadar data processing obtained from the result of GSSI surveyor 20 measurements. In addition, the Earthimager 2DINV software has been used in geoelectrical processing data from the measurement of multichannel supersting R8. Inversion from apparent resistivity to actual resistivity has been conducted to interpret subsurface section. The identified mass movement in this research have been indicated by the result of both methods the mass movement by line 1, 2, 5 with the type of translation mass movement and line 5, 7, 8 with the type of creep mass movement. Liwa subsurface structure is arranged by quartenary sediment, clay (1-100 m), sand (8 – 4000 m) and igneous rock, granit ( 5.000 – 1.000.000 m) and from the results of the data analysis found that indication of a weak zone of the fault by line 1, 2, 3, 5, 6. Keyword: Landslide, fracture, fault, georadar, geoelectricity.

A comparison of second order and high order (4 th , 8 th and 12 th order) of finite difference staggered-grid method on 2D P-SV elastic wave propagation has been conducted. The comparison plot of numerical dispersion and accuracy among each order has been generated to show the stability condition. CUDA C programming language is used to apply the finite difference staggeredgrid schema on GPU NVIDIA GeForce GTX-590 and to measure the duration of process time quantitatively. The code has been verified by comparing travel time of direct wave, reflection, refraction and conversion from the synthetic seismogram with analytical calculation from two layer medium using Snell’s law. The program is applied to one-layer medium and complex medium (Marmousi-2 model). The time process of one shot simulation on Marmousi-2 model with 4800×2400 grid size are 1168.72s (2 nd order), 1736.40s (4 th order), 2816.80s (8 th order) and 3778.67s (12 th order). The difference of seismogram showed that the second order and high order of the finite difference on two layer model indicate that the numerical dispersion has occurred on the waveform. The result shows that the higher order of the finite difference will have less numerical dispersion compared to the low order but need longer process time.

The comparison of their frequency-phase velocity (FV) diagrams from both 8 and 24 channels seismic surface wave active data (MASW) have been carried out. This conducted to show the effectiveness of smaller amounts of geophones for MASW acquitision and comparing the processing FV results. Several data were acquired both using 24 full channels geophones as well as using only 8 channels at the same line and locations. Geophone spacing for 24 channles was set to 1m and 23m total length, otherwise 3m and 21m total length for 8 channels. These two methods using 3m shot offset, by 5 kg hammer. The data were collected using the same data logger. In theory, the differences of using limited amount of geophones will be influencing the frequency-velocity bandwidth in their FV diagrams. But, this is not true for field case. Several field case shows a similar FV result for these two data, even of course there were small differences between them. For further analysis, subjective manual pickings were have similar results.

Pegunungan Bintang district with the capital Oksibil, almost all of its territory is mountains of karst, especially in the west area, people living in the mountain slopes and small valleys in small groups, scattered and isolated. Karst areas, in general, has a lot of subsurface cavities at a developed stage to form subsurface rivers. Therefore, as the capital of the District Oksibil need to know the local subsurface conditions, how much growth cavities that exist in Oksibil. So that the study was carried out by very low frequency electromagnetic (VLF) method. Based on the field measurement and VLF data analysis, the interpretation and the dolina correlation, the Oksibil area is still safe, by considering that there is no indication of dolina or subsurface river that continued relatively horizontal, and the subsurface doline at relatively quite deep (> 40 meters). electromagnetic method (VLF). The subsurface conditions is related to the presence of cavities in subsurface interconnected, while at the surface will be developed some physical facilities and others settlement building and district offices. So, given the limited surface condition that can be developed, being a good construction site is quite difficult in Pengunungan Bintang. Mapping the subsurface condition associated with the presence of cavities under the ground, for the sake of securing the future development planning on the surface that it needs supports the analysis of regional development policies in particular Oksibil district, Pegunungan Bintang, Papua province . Geophysical method uses principles of physics to study the earth. Almost all geophysical methods have been used to explore the existence of natural resources for the benefit of humans , such as oil and gas, mining materials, ground water, sources of geothermal energy and others. Geophysical method is generally performed in order to determine the existence of anomalous rock, position of the system, dimension and physical properties of the anomaly