TY - JOUR ID - 67738 TI - Kalman filter and Neural Network methods for detecting irregular variations of TEC around the time of powerful Mexico (Mw=8.2) earthquake of September 08, 2017 JO - فیزیک زمین و فضا JA - JESPHYS LA - fa SN - 2538-371X AU - Akhoondzadeh Hanzaei, Mehdi AD - Assistant Professor, Department of Remote Sensing, School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran, Iran Y1 - 2018 PY - 2018 VL - 44 IS - 4 SP - 87 EP - 97 KW - Earthquake Precursor KW - Ionosphere KW - Geomagnetic activity KW - GPS KW - Mexico earthquake KW - TEC DO - 10.22059/jesphys.2018.258251.1007007 N2 - In 98 km SW of Tres Picos in Mexico (15.022°N, 93.899°W, 47.40 km depth) a powerful earthquake of Mw=8.2 took place at 04:49:19 UTC (LT=UTC-05:00) on September 8, 2017. In this study, using three standard, classical and intelligent methods including median, Kalman filter, and Neural Network, respectively, the GPS Total Electron Content (TEC) measurements of three months were surveyed to detect the potential unusual variations around the time and location of Mexico earthquake. Every three implemented methods indicated a striking irregular variation of TEC at the earthquake time. However, on the earthquake day, the geomagnetic indices Dst and Ap have exceeded the allowed ranges and even reached maximum values during the studied time period. Besides, the solar index of F10.7 showed high activity around the earthquake day. Therefore, it is difficult to acknowledge the seismicity nature of the detected TEC unusual variations on earthquake day. Therefore, in this case, we encounter a mixed and complex behavior of ionosphere. UR - https://jesphys.ut.ac.ir/article_67738.html L1 - https://jesphys.ut.ac.ir/article_67738_ca53ea2073ad26fad3988d1e06142b16.pdf ER -