Shallow One-Dimensional Shear Wave Velocity Structure in Lhokseumawe, Aceh-Indonesia

Abstract

A series of microtremor array measurements, consisted by thirty-one sites, has been designed and conducted in Lhokseumawe. There were three lines of microtremor measurement consisting triangular seismic array for each point to study shear wave velocity model. A Spatial Auto Correlation method was applied in order to reveal the 1D velocity structure beneath the three lines at each measurement point. The analysis successfully revealed one dimensional shear wave velocity model down to 30 meters depth. The results show that the highest shear wave velocity of 639 m/s at depth of 30 m while the lowest value of 45 m/s at depth of 5 m. The results indicate that 12 out of 13 sites have low shear wave velocity with a range between 100 to 200 m/s. Low velocity structures are mainly located in Banda Sakti subdistrict. The areas with low shear wave velocity are associated with less compact sediment material which are mostly located in paddy field and ponds areas.