scholarly journals Struktur Kecepatan Gelombang Geser (Vs) di Daerah Rawan Gerakan Tanah (Longsor) Jalan Lintas Kabupaten Bengkulu Tengah-Kepahiang

2021 ◽  
Vol 11 (2) ◽  
pp. 134
Author(s):  
Nanang Sugianto ◽  
Refrizon Refrizon

Shear wave velocity <em>(V<sub>s</sub>)</em> structure at along of Central Bengkulu-Kepahiang crossline has been mapped. This research aims to identify the subsurface structure and to estimate the constituent material type of rock in landslide-prone areas (Central Bengkulu-Kepahiang crossline). Shear wave velocity structure on each site is obtained by the HVSR-inversion of 146 microtremor data (ambient noise recording of seismometer). <em>V<sub>s</sub></em> structure at the line mapped from the surface until to 30 meters of the depth. Groups of Vs are identified in class E (<em>V<sub>s</sub></em> &lt;180), Class D (180≤<em> V<sub>s</sub></em> &lt;360), Class C (360≤<em> V<sub>s</sub></em> &lt;760), and Class B (760≤<em> V<sub>s</sub></em> &lt;1500). The subsurface structure at the depth of 0 to 10 meters are dominated by stiff soil, very dense soil, and soft rock which has highly fractured and weathered rock properties. At the depth of 15 meters to 30 meters, the subsurface structure is dominated by hard rock but it is high potential or easy to fracturing and weathering like the properties of the rocks in areas that have landslides in the past. Based on <em>V<sub>s</sub></em> value, rock constituent materials are deposition of sand, clay, gravel and alluvium ranging from soft to relatively hard structures at the depth.

2015 ◽  
Vol 17 (1) ◽  
pp. 57
Author(s):  
Marjiyono Marjiyono ◽  
Hadi Suntoko ◽  
A. Soehaimi ◽  
Yuliastuti Yuliastuti ◽  
H. Syaeful

ABSTRAK KELAS SOIL DAERAH SEKITAR RENCANA TAPAK REAKTOR DAYA EKSPERIMENTAL (RDE) SERPONG DARI DATA MIKROTREMOR. Karakteristik geologi permukaan memegang peranan penting dalam analisis respon gelombang di suatu wilayah.  Sehubungan dengan rencana pembangunan Reaktor Daya Eksperimental (RDE) di Serpong, telah dilakukan pemodelan kondisi bawah permukaan dari kombinasi data mikrotremor array dan single station. Pengukuran mikrotremor array dilakukan di 9 lokasi, sedangkan single station di 90 lokasi yang tersebar pada radius ± 1 km di sekitar tapak RDE. Model bawah permukaan yang berupa struktur kecepatan gelombang geser selanjutnya dijadikan dasar untuk menghitung nilai Vs30 di daerah tersebut. Hasil klasifikasi soil berdasarkan nilai Vs30 menunjukkan kelas soil untuk wilayah sekitar tapak RDE secara umum terdiri atas kelas SD (soil menengah) dan SC (batuan lunak). Lokasi rencana tapak sendiri berada dalam wilayah kelas soil SD. Kata kunci : kelas soil, kecepatan gelombang geser, mikrotremor, tapak RDE, Vs30.   ABSTRACT SOIL CLASS AROUND THE SERPONG EXPERIMENTAL POWER REACTOR (EPR) SITE PLAN BASE ON MICROTREMOR DATA. Surface geological characteristics has an important role on site response analysis in a region. In regard with experimental power reactor (EPR) construction plan in Serpong, the subsurface modeling from combination array and single station microtremor data was done. The array and single station microtremor measurement were performed in 9 and 90 sites, respectively, at ± 1 km radius around the EPR site plan. The Vs30 value was calculated from shear wave velocity structure around the investigated area. The soil classification based on Vs30 in the investigated area generally consists of SD (medium soil) and SC (soft rock) class. The EPR site plan its self in the SD class region. Keyword : soil class, shear wave velocity, microtremor, EPR site, Vs30


1998 ◽  
Vol 41 (1) ◽  
Author(s):  
G. A. Tselentis ◽  
G. Delis

The importance of detailed knowledge of the shear-wave velocity structure of the upper geological layers was recently stressed in strong motion studies. In this work we describe an algorithm which we have developed to infer the 1D shear wave velocity structure from the inversion of multichannel surface wave dispersion data (ground-roll). Phase velocities are derived from wavenumber-frequency stacks while the inversion process is speeded up by the use of Householder transformations. Using synthetic and experimental data, we examined the applicability of the technique in deducing S-wave profiles. The comparison of the obtained results with those derived from cross-hole measurements and synthesized wave fields proved the reliability of the technique for the rapid assessment of shear wave profiles during microzonation investigations.


2010 ◽  
Vol 53 (2) ◽  
Author(s):  
Luigia Cristiano ◽  
Simona Petrosino ◽  
Gilberto Saccorotti ◽  
Matthias Ohrnberger ◽  
Roberto Scarpa

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