November 26-28, 2006 Tutorial Abstract Inversion of Electrical Resistivity Data Hee Joon Kim, Pukyong National University Although application of electrical methods began with observation of self potentials before World War II, the methods were developed slowly by the beginning of 1980's when a major burst of development activity took place. Development of smooth-model two-dimensional (2D) resistivity inversion is one of the most visible changes to geophysical interpretation of the last 40 years and is now routinely applied to dipole-dipole and pole-pole data. The ability to represent resistivities in section rather than pseudosection view has revolutionized interpretation. Resistivity methods are generally applied to environmental and geotechnical. The last two decades saw major advances in data collection, processing, and interpretation of electrical data. As with every other branch of technology, the evolving speed of the silicon chip and of streaming data to hard disk has revolutionized data collection and noise reduction processing. Previously intractable 3D inversion is now slowly becoming available. Calculation of sensitivities for general electromagnetic problems may require numerous forward modelings, but computational efficiencies are achieved if sources and receivers occupy the same position such as in resistivity methods. The way to the Exploration for Methane Hydrate Takao Inamori, JOGMEC Methane hydrate comes into the limelight as energy resource by
conventional oil or gas for energy resources of the 21st century. On the
other hand, influences to global warming by atmospheric release of
methane from the dissociation of methane hydrate or to dynamic
characteristics of methane hydrate-bearing layers below sea floor are
regarded as important factor from disaster prevention or environment.
It is well known the relationship of the Bottom Simulating Reflector
(BSR) and methane hydrate. However, we cannot estimate the amount of
methane hydrates using only the distribution of BSR.
In this seminar, I will talk topics about technology to estimate the
amount of methane hydrates using seismic reflection survey data and well
log data. GPR technology: Fundamentals to Applications Motoyuki Sato, Tohoku University and Jung-Ho Kim, KIGAM This course will be held to introduce the Ground Penetrating Radar (GPR) technology to potential users and researchers. GPR has been widely accepted in many subsurface applications in Geology, Geophysics, Hydro-geology, Archaeology, Civil Engineering and landmine detection. Especially, the GPR capability of detecting and monitoring ground water condition is remarkable. In this seminar, the fundamental technology of GPR to actual applications in various engineering fields will be introduced. GPR technology is closely related to Electromagnetic wave theory and signal processing technology. Demonstration of commercial GPR signal processing software and electromagnetic wave scattering simulation (FDTD) will be included. The High-precision Technique of Surface Deformation Monitoring Using Satellite Radar Data for geotechnical engineering application Toshimi Mizuno, OYO Corporation Abstract: The monitoring system using satellite radar data are powerful tools to clarify the ground surface motion at the area of interest. PSInSAR one of the DInSAR techniques can be extract the historical surface deformation by using multi radar data accurately, widely and densely. The results of deformation analysis of PSInSAR have proposed the new concept that the surroundings of active faults and tectonic motion are moving continuously.
This paper introduced the experiment of the historical surface deformation of Kanto Basin and the epicenter area of Chuetsu big earthquake in 2004. Slow slip of tectonic motion is very useful in order to forecast huge earthquake by Ichiro Kawasaki of Kyoto University. The slow surface deformation has much capability in order to apply geotechnical engineering, engineering geology and geophysics. Some Integrated Geotechnical-Geophysical Applications in Investigation of Soft Clays in Asia Pham Huy Giao, Asian Institute of Technology Many large-scale ground improvement and reclamation works in Asia are carried out on thick deltaic soft clay deposits, whose geotechnical characteristics are quite often not well determined partly due to soil disturbance. Investigations that the author had performed for the last five years indicated that the engineering geophysical techniques can be used as an additional and non-destructive testing tool in site investigation and characterization of theses clay deposits. Some case studies with Nakdong River (Korea), Chao Phraya River (Bangkok, Thailand), Red River (Vietnam) and Mekong River (Vietnam) deltas will be presented. The lecture contents would touch the following points:
1. Concept of an integrated geoengineering approach Electromagnetic methods: application to geothermal and other exploration Toshihiro Uchida, AIST The electromagnetic (EM) exploration method is used to delineate electrical resistivity (conductivity) structure of the underground. Resistivity is a key physical property that reflects water content and salinity, clay and other minerals, and temperature of the underground formations. Therefore, the EM method is widely applied to natural resource exploration, geotechnical engineering, groundwater and soil contamination, geological hazard mitigation, site characterization and maintenance, etc. There are various types of EM methods utilized for these purposes. Commonly used methods are magnetotellurics (MT), controlled-source audiofrequency MT (CSAMT), transient EM (TEM), airborne or on land loop-loop EM method (LLEM). The investigation depth depends on the configuration of transmitter and receiver for the measurement and the frequency of EM signals used. We choose an appropriate EM method depending on the particular target of our survey and the logistical condition of the survey area. In this lecture, some basics of the above methods as well as their application to geothermal exploration, earthquake study, groundwater exploration, and shallow geotechnical engineering will be presented. Risk Management in Civil Engineering Hiroyasu Ohtsu, Kyoto University Recently, concept of infrastructure asset management, which aims to strategically operate construction, maintenance and renewal of infrastructures has been highlighted. However, evaluation of LCC, which is selected as index for decision-making, requires modeling of various types of risk factors involved in whole phases of construction projects, since it treats unforeseeable future events. Among various types of risk factors, this paper focuses on risk costs caused by geotechnical factors on both construction phase and maintenance phase. Furthermore, in this course, scope of applicability of geo-risk engineering to geotechnical asset management is presented. Toward a better understanding of the daylight imaging method by the help of simple analytical models Hisashi Nakahara, Tohoku University Recently, an assertion has been verified experimentally and
theoretically that the Green's function between two receivers can be
reproduced by cross-correlating the records at the receivers. The
assertion is now used for passive exploration in various fields such as
geophysical exploration, ocean acoustics, helioseismology, seismology,
and so on. A basic idea seems to be traced back to pioneering papers of
Aki (1957) and Clearbout (1968) in the field of seismic exploration.
Recently, the methods based on the assertion are sometimes referred to
differently as the daylight imaging method, seismic interferometry,
coda-wave interferometry, and the retrieval of Greenfs function by
correlation. But they may have a same background. Theoretical studies on
the background for the methods are advancing, and several models have
been proposed. In this tutorial, we try to obtain a better understanding
of the daylight imaging method starting from simple models, especially
putting weight on analytical models. Though the simple analytical models
may seem to be far from reality, they surely have an advantage which
enables us to understand fundamentals of the daylight imaging method easily. Advancing Shallow Refraction Seismology with the GRM and the RCS Derecke Palmer, The University of New South Wales The generalized reciprocal method (GRM) provides maximum resolution of irregular refractors, together with the ability to accommodate undetected layers and velocity reversals under favourable conditions. The refraction convolution section (RCS) combines head wave amplitudes with the resolution of the GRM and it can address many ambiguities in refraction inversion. Furthermore, the RCS facilitates the application of many methods of processing seismic reflection, such as stacking to improve signal-to-noise ratios, prior to the measurement of traveltimes. Both the GRM and the RCS can generate excellent starting models for detailed refraction tomographic inversion. The course content is broadly focused on achieving detailed lateral resolution of seismic velocities, the use of head wave amplitudes for model parameterization and the derivation of density models, and the benefits of three dimensional (3D) methods. However, the course structure is quite flexible and specific topics of special interest, such as efficient data acquisition, velocity reversals, velocity gradients, non-uniqueness, refraction statics, etc. can be addressed.
Clock Tower Centennial Hall, Kyoto University, Kyoto, Japan.
2. How shallow is the near-surface geophysics?
3. Marriage of Geotechnics and Geophysics: why and does it make any sense? How geotechnical engineers do geophysics and vice versa?
4. Case studies in Nakdong River plain (Korea)
5. Case studies in Chao Phraya plain (Thailand)
6. Case studies in the Red River plain (Vietnam)
7. Case studies in the Mekong River plain (Vietnam)
8. Some concluding remarks