My research interest sticks understanding and monitoring of subsurface structure and state, in other words, how we can see inside the Earth, what can be observed in what way and
what can be derived from what we saw.
The basic problem establishment is how we can approach underground as heterogeneous composite material by use of wave phenomena (mainly seismic wave) with finite frequency band. Under the condition, my research focuses how we can recognize targets in underground by modeling, measurement, data analysis, signal extraction and interpretation.
ACROSS sends weak seismic signals that repeats exactly for a long time to monitor variation of subsurface states using time-lapse measurement (joint research with Prof. Yamaoka, Shizuoka Univ., JMA, etc.)
- Tokai Monitoring Experiment
- Capturing reflection signal from plate boundary and monitoring its variation.
- Observation targeted at the next Tokai Slow-Slip Event.
- Monitoring fault healing after rapture (Nojima Fault, Awaji Island)
- Monitoring volcanoes
- Sakurajima (joint research with Kagoshima Univ, Kyoto Univ, etc.)
- Development of borehole-type seismic sources (joint research with AIST)
Subsurface imaging using seismic waves
Obtain subsurface structure images and properties using natural earthquakes (aftershocks, swarms, teleseisms) and artifitial earthquakes (using active sources)
- Development of seismic data processing
- Analysis methods applicable to sparse, inhomogeneously-distribued stations that are typical to earthquake observations.
- Application to refined data analysis method using waveform information to earthquake data for higher accuracy and higher resolution
- Seismic reflection and interferometric imaging, receiver function analysis of earthquake data (joint research with JGI, etc.)
- Imaging of plate boundary using teleseismic records.
- Imaging in the crust using local and regional earthquake records.
- Imaging of basin structure using strong motion records.
- Development of seismic data processing method
- Wavefield migration/imaging
- Full wave inversion/tomography
Sensing subsurface (structure and physical properties, except heterogeneity, discontinuity and fluid) using wave phenomena.
- Extraction of information useful to monitor subsurface properties contained in observed waveforms
- Connection between the information with physical structure and state of target via physical model
- Wave propagation and rock physics, poroelasticity, fracture models
- Physical model and wave propagation of plate boundary
- What and how we can see (or can not see) in the Earth using wave phenomena
- wave propagation, imaging and inversion.
- simulation of seismic and electromagnetic wavefield.
Researches be wished to continue (but not always easy)
- Borehole seismic observation and analysis (crosswell waveform inversion, monitoring by use of tube waves and guided waves, etc.)
- 2016: TBN.
- 2014: Seismic imaging and monitoring of subsurface structure and properties, its current status and furure perspective.
- 2013: A guide (as comprehensive as possible) to seismic waveform inversion as a structure estimation problem based on wave theory.
- 2012: An approach from seismic wave propagation to the problem of estimation and monitoring of fault strength and stress accumulation at plate boundary.
- 2010: A very easy? introduction of seismic interferometry.
- 2009: Imaging subsurface structure by use of earthquakes --- commons and differences between the natural and artificial seismic source ---.
- 2007: Possibility of active monitoring of discontinuity, inhomogeneity and scatterers by use of seismic wave (II) --- wavefield modeling ---.
- 2006: Possibility of active monitoring of discontinuity, inhomogeneity and scatterers by use of seismic wave.
- 2006: Current status of ACROSS research in Nagoya University --- Towards Tokai Monitoring Experiment ---.
- 2005: What should be considered to visualize and monitor underground by use of seismic wave --- Waveform imaging for dummies ---.
- 2004: What should be considered to survey and monitor plate boundaries and faults (and contribution of fluids) by use of seismic wave --- wave propagatio, physical properties and physical models---.
- 2003: Waveform inversion of crosswell seismic data and its application to methane hydrate production monitoring.
Toshiki Watanabe, EVRC, Nagoya University.
Last modified: Tue Nov 28 16:55:22 +0900 2017