Anomalies in groundwater composition caused by earthquakes: examples and modeling issues

Abstract

The examples of modeling hydrogeochemical anomalies recorded in the observation wells and sources of Kamchatka caused by the preparation of strong local earthquakes and the impact of seismic waves are considered. As a working hypothesis explaining the formation of such anomalies, assumptions about the change of conditions (1) of mixing of two waters, contrasting in chemical composition and (2) interaction in the «water – rock» system are used.

Preseismic Groundwater Ion Content Variations: Observational Data in Flowing Wells of the Kamchatka Peninsula and Conceptual Model

“…Such a mixing can occur when hydrodynamic conditions in aquifer change or when the fracture-pore capacity of aquifer changes, as well as when the conditions for interaction of groundwater and rocks change during preparation of earthquake. In previous publications [17,19,27], we considered these probable mechanisms of hydrogeochemical anomalies in wells, giving preference to mechanism of changing the mixing conditions of contrasting waters in aquifers. This idea of the leading role of the mixing mechanism in the formation of hydrogeochemical anomalies caused by earthquakes is in good agreement with cited works of other researchers.…”

“…In this paper, using data on preseismic groundwater ion content variations and modeling, the possibility of constructing conceptual models of HGCP for individual wells is In this paper, using data on preseismic groundwater ion content variations and modeling, the possibility of constructing conceptual models of HGCP for individual wells is substantiated. A short summary of main ideas and modeling method with use a mathematical model of mixing two chemically contrasting waters in aquifer [16] were presented in [17] and in Russian in [18,19]. 1); 2, piezometric wells; 3, active volcanoes; 4, earthquake epicenters (Table 2); 5, Petropavlovsk-Kamchatsky city; 6, Petropavlovsk-Kamchatsky test site in (a).…”

Hydrogeochemical Earthquake Precursors (On the Example of Areas of the Kamchatka Peninsula, Russia, and the Republic of Uzbekistan)

“…Это дает основание полагать, что ведущим процессом формирования ГГХП является изменение условий смешивания различных по химическому составу вод в зонах повышенной водопроводимости. В качестве таких зон смешивания подземных вод различного химического состава могут рассматриваться разнообразные геологические объекты -разломные зоны (Wang et al, 2004), неоднородности трещиноватости и литологического состава водовмещающих пород («гидрогеологические окна»), а также ствол скважины при множественной перфорации обсадной колонны (Копылова, Болдина, 2012;Kopylova, Boldina, 2019).…”

“…Как показано в работах (Копылова и др., 2018;Kopylova, Boldina, 2019;Skelton et al, 2019), возникновение аномалий ГГХП в изменениях химического состава подземных вод может также происходить при изменениях взаимодействия в системе «водагорная порода» при развитии дилатансии с образованием дополнительного объема микротрещиноватости в водовмещающих породах.…”

Conditions of soils dilution of dams under seismic impacts

“…The development and improvement of methods of dynamic liquefaction of water-saturated sandy soils were carried out by Russian [1][2][3][4], Japanese [5][6][7][8], the USA [9][10][11][12], Uzbek [15][16][17][18][19][20], etc. However, they did not consider the dynamic liquefaction of cohesive soils, which sharply differ in properties from sand, which was the object of research of the author and his students [17][18][19][20].…”