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Profile photo of Ronny Berndtsson

Ronny Berndtsson

Professor, Dep Director, MECW Dep Scientific Coordinator

Profile photo of Ronny Berndtsson

Analysis of earthquake-induced groundwater level change using self-organizing maps

Author

  • Kei Nakagawa
  • Zhi Qiang Yu
  • Ronny Berndtsson
  • Makoto Kagabu

Summary, in English

For a better understanding of possible physical links between geophysical observables and earthquake characteristics, it is important to analyze statistical spatiotemporal patterns in nature related to such events. For this purpose, characteristic changes in groundwater level (GWL) were observed before and after the 2016 Kumamoto earthquake in Japan. Previous research has shown that self-organizing maps (SOM) can be used to classify complex patterns of GWL-change during different parts of the earthquake sequence. In this study, we used before and after earthquake GWL data as input vectors to SOM. In total, 64 observed GWLs were classified into 12 different clusters. Most shallow wells displayed GWL difference that was small during the foreshock (first earthquake) and large during the main-shock (second earthquake). Upstream deep wells showed relatively large difference in water level from 1 to 2 days after the earthquakes. The GWL rapidly increased just after the earthquake, then tended to gradually decrease from September. Most of the shallow wells in the unconfined aquifer rapidly recovered to initial GWLs within several hours to several days, because of hydrostatic pressure. However, most of the deep wells in the confined aquifer needed longer time to recover, in some cases several weeks to several months. These findings are important for the physical understanding of earthquake effects on the groundwater environment, disaster prevention, and possibility for development of earthquake precursors.

Department/s

  • Centre for Advanced Middle Eastern Studies (CMES)
  • MECW: The Middle East in the Contemporary World
  • Division of Water Resources Engineering
  • LTH Profile Area: Water

Publishing year

2019-08

Language

English

Publication/Series

Environmental Earth Sciences

Volume

78

Issue

15

Document type

Journal article

Publisher

Springer

Topic

  • Oceanography, Hydrology, Water Resources

Keywords

  • Cluster analysis
  • Groundwater level (GWL) change
  • Kumamoto earthquake
  • Self-organizing map (SOM)

Status

Published

ISBN/ISSN/Other

  • ISSN: 1866-6280