日本地球惑星科学連合2024年大会

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セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS04] Interdisciplinary studies on pre-earthquake processes

2024年5月26日(日) 15:30 〜 16:45 301B (幕張メッセ国際会議場)

コンビーナ:服部 克巳(千葉大学大学院理学研究科)、劉 正彦(国立中央大学太空科学研究所)、Ouzounov Dimitar(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA)、Huang Qinghua(Peking University)、座長:Ouzounov Dimitar(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA)、Jann-Yenq G Liu(National Central University)

15:30 〜 15:45

[MIS04-11] Pre-Earthquake Research: Hydrogeochemical anomalies related to the preparation phase of some earthquakes in Türkiye

★Invited Papers

Sedat Inan2、*Dimitar Ouzounov1 (1.Chapman University、2.Istanbul Technical University, Department of Geological Engineering, Istanbul - Turkiye)

Research on earthquake prediction has been carried out openly or secretly for decades. What does secret earthquake research mean? It would not be wrong to say that researches who study pre-earthquake phenomenon do not express the main purpose of their studies in order to avoid possible troubles. For short-term earthquake prediction studies, gas release from the fault zone, physical/chemical change in spring waters, changes in groundwater level, measurable electrical changes in the rock, tilt measurements in the rock, atmospheric and ionospheric changes can be mentioned. Obtaining consistent and repeatable pre-earthquake signals and making earthquake predictions based on this is a very risky issue for researchers. Because, in addition to fighting against the prejudice that "earthquakes are unpredictable", the number of earthquakes required in the studied area to prove that pre-earthquake signals can be repeated are reliable can be difficult task. There is even a possibility that no major earthquakes will occur during the project. If the targeted number of earthquakes does not occur within the scope of the project, this time the real destruction falls on the researchers. Another question frequently encountered by researchers working on earthquake prediction studies is ""assuming that earthquake prediction is possible, how do we apply it in practice?"" It happens that this unfair and untimely question means ""rolling up our sleeves without seeing the creek"" and unintentionally blocking the way of earthquake research. Because the answer to this critical question should not be expected from earth scientists, rather it is a question that should be asked to the administration responsible for emergency management, when earthquake researchers can obtain a reliable method. However, research on earthquake prediction requires organization, coordination, financial and administrative support through open-minded, multi-disciplinary, uninterrupted, and long-term work, and it must be realized as a matter of social and civil responsibility.

Since the occurrence of the devastating Kahramanmaraş earthquakes on 6 February 2023, geoscientists have been researching and documenting the characteristics of these earthquakes with multi-disciplinary approaches. Search for reliable precursors of earthquakes are important but requires systematic and long-time monitoring employing multi-disciplinary techniques. Continuous monitoring as mentioned by Inan et al. (2007) no longer exists in the Kahramanmaraş region. Therefore, in search of possible precursors, we obtained commercially bottled spring waters dated before and after the earthquakes of 6 February 2023.
Hydrogeochemical precursors have been detected in commercially bottled samples of the natural spring water (Ayran Spring) which emanates at a distance of about 100 km from the epicenters of the Mw 7.7 Kahramanmaraş (Türkiye) Earthquakes of 6 February 2023. It apparent that crustal deformation before these earthquakes caused increase in the cation/anion concentration in some commercially bottled spring waters (Ca2+, Mg2+, K+, Na+, Cl–, SO42–) through rock-water interaction. A positive anomaly that lasted at least six months was detected before the earthquakes. Similar hydrogeochemical anomalies were reported prior to Mw 7.2 Van Earthquake of 23 October 2011 (Inan et al., 2012).
Based on the results of this study and many others worldwide, we believe that studying pre-earthquake crustal deformations with multidisciplinary methods and continuous observations will enable better understanding of the earthquake processes; possibly leading to mitigation of earthquake hazards.