Effects of seismic activity on groundwater level and geothermal systems in Izmir, Western Anatolia, Turkey: the case study from October 30, 2020 Samos Earthquake

Uzelli T., Bilkic E., Ozturk B., Baba A., SÖZBİLİR H., TATAR O.

TURKISH JOURNAL OF EARTH SCIENCES, cilt.30, sa.1, ss.758-778, 2021 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 30 Sayı: 1
  • Basım Tarihi: 2021
  • Doi Numarası: 10.3906/yer-2101-9
  • Dergi Adı: TURKISH JOURNAL OF EARTH SCIENCES
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Geobase, INSPEC, TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.758-778
  • Anahtar Kelimeler: Groundwater monitoring, Samos earthquake, Bayrakli-Izmir, geothermal field, WELL-AQUIFER SYSTEMS, CHI-CHI EARTHQUAKE, MONITORING NETWORK, CONCEPTUAL-MODEL, ALLUVIAL-FAN, RESPONSES, BASIN, SENSITIVITY, ANOMALIES, IMPACTS
  • Sivas Cumhuriyet Üniversitesi Adresli: Evet

Özet

The October 30, 2020 Samos earthquake (Mw 6.6) affected the Aegean Sea and environs, caused destruction and loss of life in the city of Izmir located 70 km away from the earthquake epicenter. Before this earthquake, water resources were monitored in the areas of Bayrakli, Gulbahce, and Seferihisar. For this purpose, 10 groundwater monitoring wells were drilled in the Bayrakli area, where groundwater level, temperature, and electrical conductivity changes were monitored at 1-h intervals in 5 wells. Besides physical parameters such as groundwater levels, temperatures and electrical conductivities, hydrogeochemical cations, and anions measured in the study area. Change in the groundwater levels was observed before, during, and after the Samos earthquake. A trend of rising groundwater level was observed two days before the mainshock, to a height of 10 cm, and the level was maintained till the end of the earthquake. The water levels returned to its original height after about 7 to 10 days of the earthquake. Moreover, electrical conductivity (EC) values were changed because of the interaction with the surrounding rocks and well walls, mixing with different waters during the earthquake shaking. The essential anomalies were observed in the geothermal fields of Gulbahce and Seferihisar. Due to this earthquake, new geothermal springs emerged along the NE-SW trending Gulbahce and Tuzla faults, located about 50 to 20 km from the Samos earthquake epicenter, respectively. The new geothermal waters are in Na-Cl composition and similar to other geothermal springs in the region. While the recorded water temperatures in the new geothermal springs vary from 40 to 45 degrees C in Seferihisar, it was measured between 35 and 40 degrees C in Gulbahce. Due to these anomalies, it is found essential to monitor the effect of the earthquake on the physical and chemical characteristics of the groundwater and its usefulness in earthquake predictions.