A Complex Systems Perspective on Deceleration in Propagation Velocity of
Medium Scale Traveling Ionospheric Disturbances Before Large
Earthquakes: Unified Physical Mechanism and Multi-GNSS TEC Correlation
Analysis
Abstract
Capability of TEC ’s CoRrelation Analysis (CRA) (Iwata and Umeno,
JGR-Space Physics, 2016) for detecting preseismic anomalies is explained
from the view point of the increase in signal-to-noise ratio to amplify
preseismic TEC’s small anomaly signals with multiple sensor data
synchronization and correlation. Furthermore, deceleration at
propagation velocities of MSTID before the 2016 Kumamoto earthquake
firstly observed by CRA (Iwata and Umeno, JGR-Space Physics, 2017) as
velocity reduction of MSTID propagation in the F Layer of the ionosphere
is then elucidated as a candidate of preseismic anomalies. A new
physical model (Umeno, Nakabayashi, Iwata, Kao, 2021,DOI:
10.4236/ojer.2021.104008 ) which is recently constructed from the first
principle to explain such ionospheric anomaly (ΔV=αΔE, Linear response
theory of deceleration ΔV in propagation velocities of MSTID before
large earthquakes with electric field change ΔE) is also presented to
characterize preseismic ionospheric TEC anomalies by associating
deceleration, acceleration, moving to the inverse direction of
macroscopic ionic velocities before various large earthquakes such as
our existing findings on ionospheric TEC anomaly before 2016 Tainan
earthquake (Goto, Uchida, Igarashi, Chen, Kao, Umeno, JGR-Space Physics,
2019). In particular, this physical model predicts that the 35 m/s
change in MSTID propagation velocities estimated by TEC’s CRA for 2016
Kumamoto earthquake requires 0.58 mV/m electric field change in the F
Layer ionosphere, which is almost consistent with the estimation (Kelley
et. al. JGR-Space Physics, 2017) in that the E✖︎B/B^2 drift of 12 m/s
for dislocations of electrons requires 0.5 mV/m electric field in the E
Layer to explain Heki’s finding of TEC anomaly behavior before the
Tohoku-Oki earthquake. The 10000 times amplification effect of weak
signals such as 0.5-0.58 mV/m in electrical field to affect MSTID
propagation velocity change as is firstly observed by Iwata and Umeno,
2017 by CRA which means a significant signal amplification capability in
this multi-sensor TEC correlation analysis (CRA). To summarize, various
interrelation between physical models to exhibit TEC anomalies and
observed TEC anomalies as above will be presented to understand
preseismic ionospheric anomaly before large earthquakes.