National Central Univ., Taiwan
Pouring Taipei city
DISC events in East Asia (Taiwan, Korea, and Japan) have kicked off. The first event is at the National Central Univ. (NCU) in Taiwan. Pouring rain greeted us at Taipei Airport (June 12th). Right after we parachuted to our accommodation, the doorbell rang, and two nice looking Taiwanese guys were standing in front of the door. They are geophysicists from 3Jtech (engineering company), and were supposed to help us with our stay in Taiwan. In spite of the pouring rain, we visited the Shida night market, enjoyed lots of street food, and some taiwanese beer!
After a night in Taipei, we moved to the Tayuan District (about an hour drive), where NCU is located, thanks to a ride from Kevin. From Kevin, we learned that Taiwan has historically suffered from flooding and earthquakes, has active volcanoes indicating potential geothermal energy, and has significant water pollution problems. When we arrived at NCU, How-Wei who is the local organizer for the DISC in Taiwan (Professor at NCU), greeted us at NCU. He took us to a banquet with several Taiwanese and Chinese researchers who had just finished a joint conference. With a sip of 58 degree Chinese liquor we were ready to sleep. The excitement for the next day was high.
Our sincerest thanks are extended to How-Wei Chen for his efforts in advertising the DISC and for providing insight on topics that resonate with the Taiwanese crowd. Attendees for the course included researchers and students from NCU, the national lab (ITRI), oil companies (CPC), and industry (3JTech). Attendees brought a wide variety of backgrounds and ideas for how they would like to see EM geophysics used and areas in which they wanted to gain more insight and expertise. The audience was smaller than we had planned for but this was compensated for by the strong interaction with participants and their desire to garner more information about EM.
DISC Course at NCU, Taiwan.
As a result of our previous conversations with How-Wei, we augmented the presentation material to include: a tutorial on marine EM, a case history for gas hydrates, and some case histories using IP for landfill problems.
The incorporation of the additional material required the postponement of GPR and Natural sources until the DISC Lab day. That worked out well because almost all participants attended DISC Lab.
“Great workshop and I have learned a lot of new things” — Ping-Yu Chang (Prof., NCU) -
“Doug gave a great lecture today. He systematically introduced DC, EM, and IP methods from basic theory to advanced applications, which was useful for me.” — Tsung-Hsi (Grad student, NCU)
“I like your slides, they are so vivid and easy to understand. After the class, I got to know the whole picture about EM methods. Very impressive!” — Jimmy (Grad student, NCU) -
Most of the participants at the DISC course joined DISC lab. They were interested in the use of EM geophysics and computational tools such as SimPEG. The second day was planned to have three items: a) case history presentations from participants, b) remaining course material: MT and GPR, and c) SimPEG tutorials with the MT1D problem.
Our second day started with presentations from the participants. Six people presented the geoscience problems that they are working on.
Noise in MT data in Taiwan (link)/ Han-Lun Hsu (Postdoc at NCU)
Han-Lun showed apparent resistivity data obtained at multiple locations in Taiwan. At most of the stations there was significant noise in the frequency band of 0.1–1Hz (a period of 1–10s). The source of the noise was not clear, and this is an active research question.
Developing an MT system for Taiwan (link)/ Ping-Yu Chang (Prof. at NCU)
Ping-Yu is motivated to develop an MT system and software relevant to Taiwan, which is a highly urbanized country. His main application of the MT method will be geothermal exploration.
Ping-Yu is also curious about the effects of the Taiwan railway, which is positioned along the rim of Taiwan. There can be both DC and 60 Hz currents flowing along the railway, and some currents leak into the ground; this can be a significant source of noise in any EM method. He is planning to monitor this with a few MT stations.
Oil exploration / Henry (CPC)
Henry showed a simplified layered structure of their oil reservoir. The target (oil) is more resistive than the background, although the contrast is subtle. The use of grounded source EM was suggested, and he will start synthetic modelling to test detectability.
Lai-Lai dikes (link)/ Wen-Jeng Huang (Central geological survey, MOEA)
Wen-Jeng’s project aims to image dyke structures in coastal areas in Taiwan. DC resistivity surveys have been performed, and several 2D resistivity sections showing resistive dyke structures were presented.
Finding fault structures using DC and GPR (link) / Ray (Post doc at NCU)
Ray is a geologists, but using EM geophysics: DC and GPR to characterize active fault structures in Taiwan.
In the afternoon, Doug covered both MT and GPR, which we had not finished in the DISC day. After that, we used both the DC and MT apps to answer some questions raised from the presentations. We found using the apps are an effective way to ask questions to participants, let them to think about the physics, and immediately check whether they have right conceptual model.
After a coffee break, we gave a SimPEG tutorial using 1D MT as an example. Taiwan was the first place that we have presented a SimPEG tutorial about simulation and inversion of 1D MT data. The tutorial was effective, and people were impressed with the tutorial, and in particular how knobs in the inversion (e.g. trade-off parameter) can change the results.
After the tutorial, we wrapped up our DISC event in Taiwan. Overall, we were happy with the broad spectrum of people we met in Taiwan, and we expected some potential connections and collaborations to result (e.g. open-source MT processing package).
DISC 2017 in Taiwan would not have happened without the support from local participants to help organize logistics and encourage people to attend. In particular, How-Wei, Kevin, and Bruce.