How-Wei Chen

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How-Wei Chen
PhD Geophysics
PhD university University of Texas–Dallas

How-Wei Chen received a PhD in geophysics from the University of Texas–Dallas. He started his career in UT–Dallas as a postdoctoral and research engineer in the Center for Lithosphere Studies. Chen began his teaching and research work as a geophysics professor in National Chung Cheng University, Chiayi, Taiwan, Republic of China. Because of his contribution in strong-motion seismology studies, he was elected as the adjunct research fellow of the Institute of Earth Sciences (IES), Academia Sinica of Taiwan. In 2004, he was recruited by the School of Earth Sciences, National Central University (NCU). He was the director of the Center for Computational Geophysics (CCG-NCU) from 2009 through 2014. He is now a professor in the Institute of Geophysics, NCU. Chen served on the SEG Global Affairs Committee (GAC) for the Asia-Pacific region and world DL-HL committee member; SEG China office; ACES (APEC Cooperation for Earthquake Simulation) International Science Board (ISB). He has been an adjunct faculty member of the College of Geophysics and Information Engineering, China Petroleum University–Beijing, and visiting professor at Chungqing University of Science and Technology, China.

He is a team leader in computational seismology. His main research has been engaged mainly with seismic wave propagation in heterogeneous 2D/3D media, migration imaging, and inversion. Chen’s extended interests include integrating geophysical methods with applications to strong-motion prediction, energy-resource exploration, subsurface structure imaging, containments detection, and monitoring through field experiments, physical models, and theoretical developments. Over the years, his research experiences have included using seismic/GPR/ERT methods for near-surface/archaeology geophysics, wide-angle onshore-offshore active-source seismic exploration, strong-motion analysis and prediction studies, and large-scale tectonic structure imaging using passive source seismic data.

2016 SEG Honorary Lecturer, Pacific South

Crossing boundaries among near-surface, energy-resource exploration, earthquake, and tectonic studies

Seismic studies for earthquake and exploration seismology are being treated as separate fields because data are collected under entirely different source-and-receiver configuration. Today, infusion of different data types and acquisition modes with flexible processing strategy for simultaneously acquiring active/passive source data become inevitably necessary. An obvious example is that microseismic-event (tremor) data induced by hydraulic fracturing (“fracking”) become a new challenge for real-time imaging studies while we are searching for unconventional shale gas/oil productions. Meanwhile, tremors or repeating earthquakes have been studied extensively in earthquake seismology.

Current trends in geophysics tend to obtain 3D images of rock properties and structure features from data with preferred properties that include long-offset, wide and full azimuth; multicomponent; and effective use of coherent and incoherent signals with broadband spectral contents. However, results are still restricted by the band-limited information available.

The Asia-Pacific region suffers greatly in natural hazards in subduction zones (earthquakes, tsunamis, volcanic eruptions, tropical cyclones, and landslides). Many applications in engineering, hazard, and energy resources are all related to subsurface investigations and tend to extract reliable physical parameters. Therefore, geophysicists are in high demand, facing more practical challenges to solve real-world problems. A steady trend toward systematic searching for a unified approach becomes inevitable.

This presentation will discuss (1) the similarity in data acquisition geometry and concepts between exploration and earthquake seismology, (2) imaging principles and methods that take advantage of current advances in data acquisition and processing, and (3) potential applications in near-surface, conventional, and unconventional energy-resource exploration, earthquake hazards, and tectonic imaging studies.

A variety of imaging systems can be designed for different techniques and types of samples. Considering the effects of source path sites, wavefield simulation is essential in understanding the fundamental phenomena of seismic and electromagnetic wave propagation within the medium of interest. This talk will give an overview of the similarity, differences, and potential limitations involved in data acquisition, using wave propagation as part of the imaging process and various wave types to construct subsurface images.

For different applications, the demands for precision, accuracy, and resolution are the same and can be complementary between practical use and scientific achievement. The reliable results depend strongly on the nature of the problem, methods, a priori information of the models, and underlying theoretical assumptions and limitations to avoid any potential pitfalls.

Several designated applications include passive/active source mechanisms and signature studies; time-lapse near-surface contaminants detection and monitoring for environmental pollution; gas-hydrate exploration in marine environment; AVO/AVA and attribute analysis of GPR and seismic data; application of wave propagation in complex media for microzonation; basin amplification; and strong-motion prediction.

The conjugate processes are demonstrated, including inversion or imaging for long-offset MCS/OBS seismic data; illumination and resolution analyses; and tectonic-structure imaging based on unconventional H-κanalyses; and CCP stacking followed by receiver function migration.

This lecture also briefly outlines the physics-based overview of numeric simulators, full-waveform kernels, and their important implications. If time permits, imaging ocean-current flows from MCS data in offshore Taiwan is also a helpful approach for physical oceanography studies.

I show that understanding these essential issues can be useful in bridging many geophysical applications, including nature disaster mitigation in the Asia-Pacific region. The emphasis is on geophysical exploration, but researchers in earthquake seismology, tsunami hazards, and ocean sciences might also find the presentation useful.

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How-Wei Chen
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