Volcanic Sediment Layer of Mount Samalas 1257 AD Modeling Based on Seismic Data

Research to determine model of sediment volcanic layer of Mountain Samalas 1257 AD has been conducted in Lombok Island. Modeling based to surface wave velocity data which collect use MASW (multichannel analysis of surface wave) method. The method has applied at 6 locations in southern part relatively and models were made on southern and southeastern of eruption source. Grouping of volcanic layer was based on IBC 2003 (ICC, 2003), TSC, 1998 (Ministry of Public Works and Settlement Government of Republic of Turkey, 1998) criteria. Result of modeling was verified using outcrop at the measurement of seismic area. Volcanic layer groups that detect are C, D, E type which have velocity less than 400 ms-1 and it’s thickness less than 50 meters. The volcanic layer group consist of sand, kerikil, clay, batuapung, volcanic ash, and alluvium. All of types of volcanic rocks has founded at all seismic measurement locations with different thickness and composition.

Detection of Defects in Layered Concrete Based on Rayleigh Surface Wave Method

Based on the finite element model, the propagation characteristics of Rayleigh wave in layered structure is studied in this paper, the time-domain characteristics of wave form is analysed under different working conditions, and the identification parameters of surface wave method to detect the layered concrete is proposed. When the incident elastic wave propagates to the defect, due to the barrier effect of the defect, a part of the incident R wave is converted into a reflected R wave, which propagates along the track plate to the surface; the other part of the R wave is converted into a transmitted R wave, along the concrete. The energy amplitude can be used as one of the parameters to identify defects in the layered concrete structure.