Seasonal and Spatial Variation of Seismic Activity due to Groundwater Fluctuation in South Korea

8 pages•Published: September 20, 2018

Suk Hwan Jang, Jae-Kyoung Lee, Kyoung Doo Oh and Jun Won Jo

Abstract

We hypothesized that groundwater flow could trigger earthquakes both in the land and in the sea due to its seasonal fluctuation following the wet season. Using 1,157 earthquake data recorded starting from 1978 to 2017 by Korea Meteorological Agency monthly earthquake energy and count of occurrence were analyzed to test the hypothesis. For the earthquakes occurred in the land a six-month earthquake active period from August to January was identified, which starts two months later from the beginning of the monsoon season (June-September). Meanwhile, for the earthquakes occurred in the sea another six-month earthquake active period from February to July, delayed by six months from that of the land, was also identified. These two-month and 8-month time lags between the active periods and the monsoon season seem to be attributable to the time required for groundwater to recharge aquifer, to propagate increased hydraulic pressure through fractures and to travel from the land to the sea. Monthly earthquake count and energy series seem to support the main shock- aftershock relation proposed by the hydroseismicity model but with longer and more variable time lags (i.e. one month for the sea and three to five months for the land) than those suggested by the hydroseismicity model. An excellent correlation of earthquake energy series which means almost perfectly synchronized activation of earthquakes between the land and the South Sea having the shortest travel path with steep slope among three seas seems to be the strong evidence supporting the hydroseismicity of earthquakes occurring in South Korea. Considering constant movement of tectonic plates which builds up intraplate stress relentlessly the cyclic burst of earthquake energy release supposed to be triggered by groundwater fluctuation seems to be playing the role of invisible hands which prevent excessive accumulation of geotectonic energy in the curst. From this point of view on- going climatic change that might bring about abnormal behavior of groundwater flow may change not only the pattern but also the magnitude of earthquakes occurring in South Korea in the future.

Keyphrases: climate change, earthquake, groundwater, hydrologic cycle, monsoon

In: Goffredo La Loggia, Gabriele Freni, Valeria Puleo and Mauro De Marchis (editors). HIC 2018. 13th International Conference on Hydroinformatics, vol 3, pages 967-974.

Links:	https://easychair.org/publications/paper/l6SK
	https://doi.org/10.29007/cb6v

BibTeX entry

@inproceedings{HIC2018:Seasonal_Spatial_Variation_Seismic,
  author    = {Suk Hwan Jang and Jae-Kyoung Lee and Kyoung Doo Oh and Jun Won Jo},
  title     = {Seasonal and Spatial Variation of Seismic Activity due to Groundwater Fluctuation in South Korea},
  booktitle = {HIC 2018. 13th International Conference on Hydroinformatics},
  editor    = {Goffredo La Loggia and Gabriele Freni and Valeria Puleo and Mauro De Marchis},
  series    = {EPiC Series in Engineering},
  volume    = {3},
  publisher = {EasyChair},
  bibsource = {EasyChair, https://easychair.org},
  issn      = {2516-2330},
  url       = {/publications/paper/l6SK},
  doi       = {10.29007/cb6v},
  pages     = {967-974},
  year      = {2018}}

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