After leaving the pouring rain in Taiwan, the sunshine greeted us in Korea. Thanks to Yonghyun’s ride and Daisy’s help (from SNU), we safely parachuted into our accommodation around Seoul, and the three of us did a Bikram yoga— so, we were charged up! Korea is where Seogi is from, so we met his family and enjoyed a day hike at Gwan-ak Mountain. After spending a few days in Seoul, we moved to Dajeon where KIGAM is located. Thanks Sunkeun (from KRA) for the ride and for the incredible lunch! We visited KIGAM briefly, and checked out our room and its facility with Myeong-Jong’s (from KIGAM) help. It was one of the best rooms that we have had. After that, we met Jungho (from KIGAM) and had a Korean BBQ dinner; this was a great prelude to the DISC day at Korea.
Around 60 people were registered; the majority of them were graduate students from various Universities: Seoul National, Hanyang, Kangwon, Sejong, and Inha. There were also some professionals from KIGAM and KRA. Most of the students had previously been introduced to some applications of EM. Their research interests were diverse: oil and gas, mining, ground water, and dam safety.
Since they were a quiet audience, it was a challenge for us to diagnose whether they were following along with us or not. We ended up asking questions of participants by University, and it was an effective way to engage the students in the course. We went through DC, EM fundamentals, and inductive source before lunch.
Around lunch time, we introduced a DC app with azure notebooks. With the app, participants were able to check their understanding about the DC resistivity method that they were introduced to in the morning. In the afternoon, we covered most of the other material, except GPR — we planned to cover the content left over on the next day. Most participants planned to come DISC lab, and seven people volunteered to present their research.
The presentations were very impressive and helpful. The basic theory is easily understood, and applications are very helpful. I learned a lot from the course. — Dong-Joo Min, Professor at SNU -
I could correct my misunderstandings, because almost every important part of EM theory was covered in this course, which was very valuable! — Yonghyun Chung, Researcher at SNU -
Very good and intuitive course. Enthusiastic lecture and demonstrations. — Sung Kon Lee, Researcher at KIGAM -
Most of the participants attended DISC lab. In the morning, Doug covered items that we did not get to on the first day: GPR, UXO, and the application of IP for monitoring Landfills. Different from my expectations, UXO seemed not to be a significant issue in Korea. Recently in Korea, GPR has gained significant interest for locating and characterizing cavities in highly urbanized areas.
After coffee break, eight participants presented their research and case histories:
Ocean crosswell EM survey (link) / Jun-yeong Heo, SNU
- Jun-yeong is interested in monitoring CO2 using a cross well EM survey and is curious about effects of steel casing.
MT survey at the Century zinc mine (link) / Sungkon Lee, KIGAM
- Sungkon acquired MT data, processed it, and interpreted it to understand the fault structure at the Century Zinc mine. Interestingly, UBC interpreted the DC and IP data at the same mine, and those results were presented in the DISC.
Steel casing problem in EM (link) / Sukmin Oh, Hanyang Univ.
- Sukmin is interested in developing an EM forward simulation algorithm for steel casing using an integral equation approach.
Modified electrical survey for effective leakage search (link) / Bomi Lee, Kangwon Univ.
- Bomi is interested in using the DC method to monitor leakage at dam with a modified array.
Groundwater (link) / Sungkeun Lim, KRA
- Sungkeun wants to find freshwater in coastal areas, and also wants to know how far it extends off the coast. In addition, his company is interested in finding seawater inland in coastal areas to provide water for fish farms.
Negative apparent chargeability (link) / Bitnare Kim, Sejong Univ.
- Bitnare’s research is focused on understanding negative apparent chargeability.
Data kernel in the Laplace domain (link) / Jungmin Kwon, Seoul National Univ.
- Jungmin is focused on seismic methods, and in particular handling data in the Laplace domain.
GREATEM and EM survey in Korea (link) / Myeong-Jong, KIGAM
- Myeong-Jong and his team are testing which airborne EM (AEM) systems are effective for mapping Korean geology. Some frequency domain AEM systems were tested and shown to be effective for mapping very near surface geology (~80 m). For a deeper mapping, GREATEM was tested, which use long grounded wire as a source, and measures magnetic fields in the air.
1D MT tutorial
After the presentations from the participants, we presented a 1D MT tutorial. We briefly discussed the MT method using the MT layered app, then moved to the 1D MT tutorial using SimPEG. The tutorial is structured to discuss the numerical simulation and inversion. In the simulation, we show how Maxwell’s equations can be discretized using the finite difference method and implemented using SimPEG. We then discussed non-uniqueness using an example of a thin layer, varying the thickness while preserving the conductivity-thickness product. We ran some 1D inversions with different sets of inversion parameters and showed the impact of each parameter in the inversion result. With those examples, we emphasized how critical the user should be when interpreting inversion results. Students were engaged, and they are interested in using EM GeoSci and SimPEG for their research.
DISC 2017 in Korea would not have happened without the support from local participants to help organize logistics and encourage people to attend — In particular, Jungho, Daisy, Myeong -Jong, Yonghyun, and Sungkeun.
Behind the scene …
We enjoyed a foot bath after the two day DISC events. How nice and warm! Half of the East Asian leg is over.