NH003-0004
Observing of pre-earthquake transients features in atmosphere-ionosphere associated with January 2020 Caribbean earthquakes

Monday, 7 December 2020
Poster
Dimitar Ouzounov1, Sergey A Pulinets2, Dmitry Davidenko3, Alexander Rozhnoi4, Mariya Solovieva5, Menas Kafatos1, Andrew Papilion6 and Patrick T Taylor7, (1)Chapman University, Center of Excellence in Earth Systems Modeling & Observations, Orange, CA, United States, (2)Space Research Institute (IKI), Moscow, Russia, (3)Space Corporation Energiya, Moscow, Russia, (4)Institute of Physics of the Earth, Moskow, Russia, (5)Institute of Physics of the Earth, Moscow, Russia, (6)Chapman University, Center of Excellence in Earth Systems Modeling & Observations, Orange, VA, United States, (7)NASA Goddard Space Flight Center, Code 61A, Greenbelt, MD, United States
Abstract:
Several significant earthquakes occurred in the Caribbean during January 2020. The first earthquake with M = 6.4 occurred on January 7 off the southern coast of Puerto Rico. An earthquake of M7.7 occurred in the Caribbean Sea on January 28, 2020, around 19:10 UT on the island of Jamaica. After 3 hours (21:55), another M 6.1 earthquake (NEIC / USGS) occurred in the Caribbean. We analyzed, retrospectively, four different atmosphere/ionosphere physical parameters of during the time of these earthquakes namely: (i) the lower atmosphere chemical potential (ACP); (ii) outgoing earth radiation (OLR) at the TOA; (iii) GPS/TEC and; (iv) the very-low-frequency (VLF/LF) signals. We found that at the beginning of January 2020, a rapid increase in satellite measurements of the earth’s atmosphere radiation was recorded, an anomaly appeared over Puerto Rico on January 6 (1 day before the M6.4), and the maxim anomaly appeared eastward from January 20 (eight days before the M7.7). The increases in ACP on January 20-23 were measured near the epicentral area of the M7.7 event and coincided with the OLR anomaly. For the VLF analysis, we used the amplitude data of the NAU signal (signal frequency 40.75 kHz), which was received at Chapman University in Orange, California. The length of the signal propagation path from the transmitter to the receiver was about 5300 km. A significant decrease in signal amplitude, exceeding the level of two standard deviations, was observed before the January 7 earthquake (M = 6.4) off the coast of Puerto Rico. A more significant anomaly in the VLF signal was observed before the M7.7 earthquake on January 28.
The pre-earthquake nature of the signals in the atmosphere and ionosphere was revealed by simultaneous analysis of satellite, GPS/TEC, and VLF/LF observations. They suggest that they follow a general temporal-spatial evolution pattern, which has been previously observed globally.

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