[H-DS09] Human environment and disaster risk

[HDS09-P07] Preliminary Evaluation of DAS data recorded throughout Fiber Optical Cable on the bottom of Marmara Sea, Türkiye

*AHMET ANIL DINDAR¹, AITARO KATO², BULENT AKBAS¹, SELCUK TOPRAK¹, CEREN OZER SOZDINLER¹, DOGAN KALAFAT³, SULEYMAN TUNC⁴, YOSHIYUKI KANEDA⁵ (1.GEBZE TECHNICAL UNIVERSITY, 2.UNIVERSITY OF TOKYO, 3.BOGAZICI UNIVERSITY, 4.SENTEZ ENGINEERING CO., 5.KAGAWA UNIVERSITY)

Keywords:NORTH ANATOLIAN FAULT ZONE, DIGITAL ACOUSTIC SENSING, FIBER OPTIC CABLE, OCEAN BOTTOM SEISMOMETER

North Anatolian Fault Zone (NAFZ) which crosses through the entire Türkiye from the far west to east has been one of the most active tectonic structures in the World that created several major earthquakes with magnitudes over 7 in the last century. The earthquake sequences historically proceeded from east to west of NAFZ. The most recent earthquake of magnitude Mw=7.4 struck in 1999 in the vicinity of Izmit province on the east end of Marmara Sea. Even though the earth observation networks such as strong ground motion and GNSS stations have been operated on either side of NAFZ, monitoring the segments of NAFZ under Marmara Sea is a challenging task. As part of the previous SATREPS project, called MARDIM that was successfully conducted between 2013-2018, a network of Ocean Bottom Seismometer (OBS) were temporarily placed on the west part of Marmara Sea for monitoring the seismic events. Following the valuable data set obtained from OBS observations during those years, a second SATREPS project, called MARTEST, was initiated as of June 2023 and expected to complete by 2028. The scope of MARTEST project includes the deployment of OBS stations in the east part of Marmara Sea and process of Digital Acoustic Sensing data recorded on two fiber optic cables that have been in use for communication. The two cables, at a length of 8 km and 26 km, cross over the east segment of NAFZ under the Marmara Sea. The DAS data recording from the cables will start as of mid-April 2024 using a brand-new interrogator. The initial tests on the recorded data will be the benchmarking of the quality of data and also determination of the signal characteristics (noise, reliability, accuracy etc.) from both of the cables. The preliminary results of the initial test will be presented in JPGU 2024. The more comprehensive process of DAS data in the light of OBS recordings as well as seismic/GNSS stations will start in the beginning of 2024 summer.