Technical NoteEarthquake dates and water level changes in wells in the Eskisehir region, Turkey

Abstract

Although satisfactory results have yet to be obtained in earthquake prediction, one of the most common indicators of an anomalous precursor is a change in groundwater level in existing wells. Further wells should thus be drilled in unconfined aquifers since these are more susceptible to seismic waves. The Eskisehir region lies in the transition zone between the Aegean extensional domain and the compressible northern Anatolian block. Limnigraphs, installed in 19 exploration wells in the Eskisehir region, recorded pre-seismic, co-seismic and post-seismic level changes during the earthquakes of 17 August Izmit (Mw = 7.4) and 12 November Duzce (Mw =7.2) 1999 that occurred along the North Anatolian Fault Zone. The Izmit and Duzce earthquakes affected groundwater levels, especially in confined aquifers. The aquifer characteristics before and after the earthquakes were unchanged so the aquifer is elastic in its behaviour. Further detailed geo-mechanical investigation of the confined aquifer in the Eskisehir region may improve understanding of earthquake prediction.

Geodetic observations of post-seismic transients in the context of the earthquake deformation cycle

“…Hydrothermal activity seems to have changed prior to the 1989 Loma Prieta earthquake in California [108]. The level of water in wells changed during or following the 1999 earthquakes in Turkey [121]. Similar effects were observed in an abandoned mine over several months after a M w 7.2 earthquake in Japan [79].…”

Previous, Current, and Future Trends in Research into Earthquake Precursors in Geofluids

“…In the period 1984-1989, groundwater levels (six monitoring stations) and radon activity (five monitoring stations) were measured along with other geophysical parameters in Turkey [100]. The lack of powerful earthquakes during the observation period hindered the final findings, but major technological and operational improvements have been made in groundwater monitoring and data analysis techniques, as [101][102][103] reported precursory variations in geofluid in wells and in selected springs in Turkey in 2006. Inan and coworkers led the deployment of several radon monitoring stations in soils and some wells in 2007, but no definitive results were obtained in the following years [104,105].…”

On investigations of the observed thermal anomaly in earthquake precursors: A case study from the 1993 Latur earthquake prone area in western India

“…A variety of earthquake precursors, including geophysical, geochemical (Barsukov et al 1985;King 1986), geodetic, biophysical, thermal (Guangmeng 2008), and other phenomena have been identified preceding major earthquakes. Some of these precursors include: the sudden change in seismicity characterized by seismic bvalue characterizing the magnitude-frequency distribution, and fractal dimension of spatio-temporal distribution of epicenetrs (Dimri 2005a(Dimri , 2005bRavi Prakash and Dimri, 2000), fluctuation in ground-water levels due to change in stress (Yuce and Ugurluoglu 2003), change of gravity and magnetic field of earth and electrical resistivity of sub-surface rock materials, including self-potential values (Hayakawa and Fujinawa 1994;Noritomi 1978;Hayakawa and Fujinawa 1994), release of Radon and Helium gas (Wakita et al 1978), rise in skin surface and atmospheric temperature (Choudhury et al 2006;Guangmeng 2008), atmospheric storm-related wind drag on continents, fault zone rock layer heating associated with the solar and geomagnetic storms, difference in electromagnetic emission (ULF/VLF).…”

“…Geochemical and hydrological signals preceding the major earthquakes have been used for earthquake prediction, especially in China, Japan, the former Soviet Union, and the United States (King 1986). Yuce and Ugurluoglu (2003) have shown the ground water level changes in 19 exploration wells and recorded pre-seismic, co-seismic, and post-seismic water level changes during the Izmit and Duzce earthquakes in the Eskisehir region, Turkey.…”