Transient effects in the atmosphere/ionosphere and their re-occurrence before large earthquakes. Case study for the 2022 “anniversary” events.

<p>We present a study on temporal and spatial characteristics of Thermal Radiation anomalies (TRA) and ionospheric total electron content (TEC) pre-earthquake abnormalities associated with the occurred in 2022 &#8220;anniversary&#8221; earthquakes. &#8220;Anniversary&#8221;&#160; is a quake occurring on the same date and following the years after the main earthquake, plus or minus several days.</p> <p>We studied eleven large earthquakes in four regions:&#160;i/Japan: M7.3 of 03.16.2022 and M9.0 of 03.11.2011&#160;East Coast&#160;Honshu;&#160;ii/Mexico: M7.6 of 09.19.2022&#160;Michoacan; M7.1 of 09.19.2017 Puebla and M8.0 of 09.19.1985 Mexico City;/iii Chile:&#160;M5.7 02.28.2022&#160;Bio-Bio&#160;and M8.8 02.27.2010&#160;Maule&#160;and&#160;/iv Taiwan: M6.9 of 09.18.2022 Taitung and M7.7 of 09.21.1999 Chi-Chil and M6.7 of 03.22.2022 Taitung and M6 of 03.27.2013 Nantou earthquake.</p> <p>We analyzed for TRA and TEC anomalies concerning the earthquake preparation zone (EPZ). For EPZ estimates, we use Dobrovolsky et al. (1979), and Bowman et al. (1998) estimates where the EPZ radius scales exponentially with earthquake magnitude, especially from Mw &#8805; 6.0 onwards, and gives an extended coverage at larger magnitudes to examine TRA and ionospheric TEC anomalies. The main goals of this study were: 1/to understand the seismotectonic conditions that preceded the earthquake re-occurrence in the same place and on the same day(s): 2/ to perform a validation study about pre-earthquake signal occurrences in the same atmospheric and solar-geophysical conditions and 3/ to understand the potential triggering mechanism. Our preliminary results show synergetic coordination between the appearance of pre-earthquake transients&#8217; effects in the atmosphere and ionosphere (with a short time lag, from hours up to a few days). The spatial characteristics of pre-earthquake anomalies were associated with the large area but inside the preparation region estimated by Dobrovolsky-Bowman. The pre-earthquake nature of the signals in the atmosphere and ionosphere was revealed by simultaneous analysis of satellite, GPS/TEC, and Satellite Earth observations. The &#8220;anniversary&#8221; events are recognized with common pre-earthquake transient re-occurrence patterns in the atmosphere/ionosphere within EPZ, scaled to the extent of the earthquake magnitude.</p>