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Effects of the Japanese 2016 kumamoto earthquake on nitrate content in groundwater supply

Nakagawa, Kei LU orcid ; Shimada, Jun ; Yu, Zhi Qiang ; Ide, Kiyoshi and Berndtsson, Ronny LU orcid (2021) In Minerals 11(1).
Abstract

The 2016 Kumamoto earthquake had a significant impact on groundwater levels and quality. In some areas, the groundwater level increased significantly due to the release of groundwater from upstream mountainous regions. Conversely, the groundwater level in other areas greatly decreased due to the creation of new fracture networks by the earthquake. There were also significant changes in certain groundwater quality variables. In this study, we used clustering based SOM (self-organizing maps) analysis to improve the understanding of earthquake effects on groundwater quality. We were especially interested in effects on groundwater used for drinking purposes and in nitrate concentration. For this purpose, we studied groundwater nitrate (NO3... (More)

The 2016 Kumamoto earthquake had a significant impact on groundwater levels and quality. In some areas, the groundwater level increased significantly due to the release of groundwater from upstream mountainous regions. Conversely, the groundwater level in other areas greatly decreased due to the creation of new fracture networks by the earthquake. There were also significant changes in certain groundwater quality variables. In this study, we used clustering based SOM (self-organizing maps) analysis to improve the understanding of earthquake effects on groundwater quality. We were especially interested in effects on groundwater used for drinking purposes and in nitrate concentration. For this purpose, we studied groundwater nitrate (NO3 + NO2–N) concentrations for the period 2012–2017. Nitrate concentration changes were classified into seven typical SOM clusters. The clusters were distributed in three representative geographical regions: A high concentration region (>4 mg/L), a low concentration region (<1.6 mg/L) with minimal anthropogenic loading area, and an intermediate concentration region (2–4 mg/L). Depending on these regions, the nitrate concentration changes just before and after the earthquake had both increasing and decreasing trends between 2015–2017. This points to complex physiographical relationships for release of stored upstream groundwater, promotion of infiltration of shallow soil water/groundwater, and nitrate concentration as affected by earthquakes. We present an analysis of these complex relationships and a discussion of causes of nitrate concentration changes due to earthquakes.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
2016 Kumamoto earthquake, Groundwater, Nitrate, Self-organizing maps
in
Minerals
volume
11
issue
1
article number
43
pages
17 pages
publisher
MDPI AG
external identifiers
  • scopus:85099156408
ISSN
2075-163X
DOI
10.3390/min11010043
language
English
LU publication?
yes
id
25b5812e-5676-4aeb-814c-89fa5016833a
date added to LUP
2021-01-20 10:59:50
date last changed
2023-10-08 20:14:02
@article{25b5812e-5676-4aeb-814c-89fa5016833a,
  abstract     = {{<p>The 2016 Kumamoto earthquake had a significant impact on groundwater levels and quality. In some areas, the groundwater level increased significantly due to the release of groundwater from upstream mountainous regions. Conversely, the groundwater level in other areas greatly decreased due to the creation of new fracture networks by the earthquake. There were also significant changes in certain groundwater quality variables. In this study, we used clustering based SOM (self-organizing maps) analysis to improve the understanding of earthquake effects on groundwater quality. We were especially interested in effects on groundwater used for drinking purposes and in nitrate concentration. For this purpose, we studied groundwater nitrate (NO3 + NO2–N) concentrations for the period 2012–2017. Nitrate concentration changes were classified into seven typical SOM clusters. The clusters were distributed in three representative geographical regions: A high concentration region (&gt;4 mg/L), a low concentration region (&lt;1.6 mg/L) with minimal anthropogenic loading area, and an intermediate concentration region (2–4 mg/L). Depending on these regions, the nitrate concentration changes just before and after the earthquake had both increasing and decreasing trends between 2015–2017. This points to complex physiographical relationships for release of stored upstream groundwater, promotion of infiltration of shallow soil water/groundwater, and nitrate concentration as affected by earthquakes. We present an analysis of these complex relationships and a discussion of causes of nitrate concentration changes due to earthquakes.</p>}},
  author       = {{Nakagawa, Kei and Shimada, Jun and Yu, Zhi Qiang and Ide, Kiyoshi and Berndtsson, Ronny}},
  issn         = {{2075-163X}},
  keywords     = {{2016 Kumamoto earthquake; Groundwater; Nitrate; Self-organizing maps}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{MDPI AG}},
  series       = {{Minerals}},
  title        = {{Effects of the Japanese 2016 kumamoto earthquake on nitrate content in groundwater supply}},
  url          = {{http://dx.doi.org/10.3390/min11010043}},
  doi          = {{10.3390/min11010043}},
  volume       = {{11}},
  year         = {{2021}},
}