The aftermath of Japan’s 7.6 earthquake even shook the groundwater of the Korean Peninsula.
The Korea Institute of Geoscience and Mineral Resources (KIGAM) Groundwater Environment Research Center observed changes in groundwater levels at three domestic groundwater observation wells (Mungyeong, Gangneung, and Yanggu) after the 7.6 earthquake that occurred in Japan on the 1st, and found that the tsunami also affected changes in groundwater levels in Korea. It was announced on the 10th that it was confirmed for the first time that it affects.
First, it was confirmed that at the Mungyeong groundwater observation well, located about 800 km away from the epicenter, the change in groundwater level reached a maximum of 107.1 cm due to the influence of seismic waves.
Additionally, the change time was 3 hours, and repeated rise and fall phenomena were detected through monitoring at 1-second intervals.
At the Yanggu groundwater observation well, the groundwater level showed an instantaneous drop due to the influence of the same seismic wave. The rapid drop in groundwater levels suggests the possibility of groundwater leaking.
The Gangneung groundwater observation well observed changes in groundwater levels due to the tsunami for the first time in Korea.
The tsunami reached Mukho Port around 6:05 p.m. on the 1st, and a change in groundwater level of about 10 cm lasted for about 10 hours from 6:10 p.m. to 4:10 a.m. the next day.
From the observation results, it can be inferred that a tsunami can not only cause seawater to flow into the coastal aquifer (seawater infiltration), but also affect the stability of the coastal ground.
In particular, the Gangneung groundwater observation well can be said to be vulnerable to groundwater fluctuations as it has a structure that can be easily affected by seawater due to the large number of cavities distributed.
In addition, because the impact of a tsunami may vary depending on ocean tidal phenomena, continuous observation and prediction checks (simulation) of tsunami groundwater level changes considering ocean tides are necessary.
Lee Soo-hyung, a senior researcher at the Korea Institute of Geoscience and Mineral Resources who led the study, said, “If a strong earthquake occurs in a neighboring country, it is expected to have an impact on the domestic underground environment, including changes in groundwater quantity and quality.” “It can be said to be a meaningful research result in that it can have an impact on the environment.”
Lee Pyeong-gu, director of the Korea Institute of Geoscience and Mineral Resources, said, “Even if it is not due to the impact of the Japanese earthquake, the risk of a tsunami remains on the east coast of the Korean Peninsula.” He added, “Using the state-of-the-art physical exploration and research vessel Tamhae 3, which will enter service in May, we will conduct submarine fault surveys and detailed seafloor research. “We plan to draw up a topographic map,” he said.
(DaejeonㆍChungnam = News 1)
Source: Donga
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