Pelatihan : Techniques in Active Tectonic Study Juni 20-Juli 2, 2013 Instruktur: Prof. J Ramon Arrowsmith (JRA) Dari Arizona State University (ASU) - US Tempat Pelaksanaan: Ruang Pangea, Laboratorium Gempabumi (LabEarth) – Puslit Geoteknologi LIPI dan Kuliah lapangan akan dilakukan disekitar Sesar Lembang, Jawa Barat. * Lebih jelas baca TOR/KAK dan daftar acara

Shallow geophysics and cone penetrometer testing Outline of this lecture “remote sensing” of the subsurface (geophysics and drilling) – Seismic methods – CHiRP applied to subaqueous – GeoRadar – Electrical resistivity Cone Penetrometer Testing (CPT) Much of this lecture comes from this excellent book

“remote sensing” of the subsurface (geophysics and drilling) Define shallow stratigraphy and structure Trace faults to greater depth than can be reached with trenching Detect buried faults Depth scales can be a few meters to a few km

Seismic reflection geometry Simple zero offset Multilayer Increase signal strength with folding and stacking

Seismic reflection and refraction

CHIRP profiling, coring, bathymetry

Flying ITB to Lake Tahoe, California

Exploring Lake Tahoe, California (USGS)

Profiles were collected with the Edgetech SubScan Chirp system. Chirp profiles presented here use a 1–5.5 kHz pulse with a 10 ms duration, a 1–5.5 kHz pulse with 30 ms duration, or a 1–6 kHz pulse witha 50 ms duration (Smith, et al., 2013) CHIRP: A type of sonar technology utilizing separate projector and hydrophone where the projector transmits digitally produced, linear, swept FM pulses resulting in an increased system bandwidth. As these systems are multifrequency, greater bandwidth rather than the pulse length results in higher theoretical range resolution. Chirp technology has been successfully used in sub-bottom profilers and is being developed for long-range side-scan applications.

GeoRadar or Ground Penetrating Radar Similar principles as seismic reflection except that a microwave signal is used and return signals are reflected from materials with different dielectric constants.

GeoRadar

Electrical Resistivity Tomography-- a geophysical technique for imaging sub-surface structures from electrical resistivity measurements made at the surface, or by electrodes in one or more boreholes (

Cone penetrometer test (CPT) Grant et al, 1997 Tip cone CPT Rig G. Marliyani

Standard Penetration Test Rotary-drilled Borehole Standard Penetration Test (SPT) Procedures: ASTM D 1586 N = measured Number of Blows to drive sampler 300 mm into soil. Paul W. Mayne

Cone Penetration Tests (CPT) Mobile 25-tonne rigs with enclosed cabins to allow testing under all weather conditions Cone Trucks Paul W. Mayne

CPT and Trenches transect Total 38 CPT soundings Seven shallow trenches ( ) G. Marliyani

400m long trench 2009 Trench Trench 1, Summer 2009 G. Marliyani

CPT Profile 1 G. Marliyani

CPT Profile 2 G. Marliyani

Shallow geophysics and cone penetrometer testing Outline of this lecture “remote sensing” of the subsurface (geophysics and drilling) – Seismic methods – CHiRP applied to subaqueous – GeoRadar – Electrical resistivity Cone Penetrometer Testing (CPT) Much of this lecture comes from this excellent book