Effects of the Japanese 2016 Kumamoto Earthquake on Nitrate Content in Groundwater Supply

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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Changes of Groundwater Quality in the Sorrounding Pollution Sources Due to Earthquake Dissaster

Forum Geografi ◽

10.23917/forgeo.v20i2.1813 ◽

2016 ◽

Vol 20 (2) ◽

Author(s):

Sudarmadji Sudarmadji

Keyword(s):

Groundwater Quality ◽

Groundwater Level ◽

Local Community ◽

Pollution Sources ◽

Quality Changes ◽

Underground Structures ◽

Domestic Water ◽

Septic Tanks ◽

Groundwater Supply ◽

Dug Well

Groundwater is the main domestic water supply of the population of the Yogyakarta Special Region, both in the urban and as well as in the rural area due to its quantity and quality advantages. The rapid population growth has caused an increase of groundwater demand, consequently it is facing some problems to the sustainability of groundwater supply. Lowering of groundwater level has been observed in some places, as well as the degradation of groundwater quality. Earthquake which stroke Yogyakarta on 27 May 2006, damaged buildings and other infrastructures in the area, including roads and bridges. It might also damage the underground structures such as septic tanks, and pipes underneath the earth surface. It might cause cracking of the geologic structures. Furthermore, the damage of underneath infrastructures might create groundwater quality changes in the area. Some complains of local community on lowering and increasing groundwater level and groundwater quality changes were noted. Field observation and investigation were conducted, including collection of groundwater samples close to (the) pollution sources. Laboratory analyses indicated that some parameters increased to exceed the drinking water quality standards. The high content of Coli form bacteria possibly was caused by contamination of nearby septic tanks or other pollution sources to the observed groundwater in the dug well.

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Influence of the 2016 Kumamoto earthquake on groundwater quality

Japanese Journal of Limnology (Rikusuigaku Zasshi) ◽

10.3739/rikusui.79.147 ◽

2018 ◽

Vol 79 (3) ◽

pp. 147-159 ◽

Cited By ~ 5

Author(s):

Yasunori KAWAGOSHI ◽

Hitomi KOGA ◽

Yuichi SUENAGA ◽

Takehide HAMA ◽

Hiroaki ITO

Keyword(s):

Groundwater Quality ◽

2016 Kumamoto Earthquake ◽

Kumamoto Earthquake ◽

The 2016 Kumamoto Earthquake

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Assessment and Prediction of Groundwater using Geospatial and ANN modeling

10.21203/rs.3.rs-246464/v1 ◽

2021 ◽

Author(s):

Ankita Pran Dadhich ◽

Rohit Goyal ◽

Pran Nath Dadhich

Keyword(s):

Water Quality ◽

Time Series ◽

Groundwater Quality ◽

Water Level ◽

Groundwater Level ◽

Quality Parameters ◽

Time Series Forecasting ◽

Nitrate Content ◽

Human Consumption ◽

Forecasting Models

Abstract In semi-arid regions the deterioration in groundwater quality and drop in water level upshots the importance of spatio-temporal mapping with geospatial and advanced modeling techniques. In present study, changes in water level, water quality trend patterns and future scenarios of groundwater in 171 villages of Phagi tehsil, Jaipur district was assessed using eight years (2012-2019) groundwater data. Spatial interpolation maps were drawn using kriging method for pre-monsoon season and integrated with three different time series forecasting models (Simple Exponential Smoothing, Holt's Trend Method, ARIMA) and Artificial Neural Network models to ascertain the optimal prediction for groundwater level and quality parameters. Results reveal that the use of ANN model can describe the behavior of groundwater level and quality parameters more accurately than time series forecasting models. In addition, different ANN algorithms were tested to select the best-performing algorithm and ANN15 is found the most accurate one in simulating the magnitude and patterns of pre-monsoon water level data for year 2019 with R2 = 0.98, and NSE = 0.81. The change in groundwater table was observed with more than 4.0m rise in 81 villages during 2012-2013 whereas ANNpredicted results of 2023-2024 infer no rise in water table (>4.0m). Water level drop of more than 6.0m was observed in 16 villages of Phagi tehsil based on predicted results of 2024. Assessment of groundwater quality parameters like Total dissolved solids, chloride, fluoride and nitrate indicate chemically unsuitable groundwater for drinking purpose in most part of the Phagi. ANNpredictions point out excess nitrate content in 58% villages however, Water quality Index reveals unfit groundwater in 74% villages for human consumption in 2024. This time series and projected outcome of groundwater at village level can assist the planners and decision-makers for proper management of groundwater risk areas.

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Changes in the nitrate concentration of spring water after the 2016 Kumamoto earthquake

Journal of Hydrology ◽

10.1016/j.jhydrol.2019.124310 ◽

2020 ◽

Vol 580 ◽

pp. 124310 ◽

Cited By ~ 5

Author(s):

Tsutomu Sato ◽

Hiroshi A. Takahashi ◽

Kuniyo Kawabata ◽

Masaaki Takahashi ◽

Akihiko Inamura ◽

...

Keyword(s):

Nitrate Concentration ◽

Spring Water ◽

2016 Kumamoto Earthquake ◽

Kumamoto Earthquake ◽

The 2016 Kumamoto Earthquake

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Seasonal and transient surface displacements in the Kumamoto area, Japan, associated with the 2016 Kumamoto earthquake: implications for seismic-induced groundwater level change

Earth Planets and Space ◽

10.1186/s40623-020-01275-2 ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Kazuya Ishitsuka ◽

Takeshi Tsuji ◽

Weiren Lin ◽

Makoto Kagabu ◽

Jun Shimada

Keyword(s):

Groundwater Level ◽

Surface Displacement ◽

Earthquake Sequence ◽

2016 Kumamoto Earthquake ◽

Persistent Scatterer Interferometry ◽

Kumamoto Earthquake ◽

Level Change ◽

Surface Displacements ◽

The 2016 Kumamoto Earthquake ◽

Groundwater Level Change

Abstract The 2016 Kumamoto earthquake sequence on April 14 (Mw 6.2) and April 16 (Mw 7.0) altered the regional groundwater level. To better understand the relationship between groundwater level change and surface displacement, we estimated surface displacement in the Kumamoto area (Japan) using persistent scatterer interferometry from 19 ALOS/PALSAR images acquired between January 7, 2007 and March 5, 2011, 28 ALOS-2/PALSAR-2 images acquired between April 17, 2016 and December 10, 2018, and 113 Sentinel-1 images acquired between May 26, 2016 and December 30, 2018. Our estimation shows that transient surface displacement occurred following the 2016 Kumamoto earthquake sequence, together with seasonal surface displacement that was not detected from the 2007–2011 images. We suggest that a portion of the transient displacement occurred via groundwater drawdown through new ruptures that formed owing to the 2016 Kumamoto earthquake sequence and sediment compaction. Seasonal surface displacements detected after the 2016 Kumamoto earthquake sequence are linked to groundwater level variations.

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