The Outgoing Longwave Radiation Analysis of Medium and Strong Earthquakes

Abstract

Two approaches are applied to outgoing longwave radiation (OLR) data to obtain abnormal changes before and after six earthquakes: the background field analysis method, which focuses on statistically processing the increment of a radiation value to the multi-year average of the data; and the tidal force fluctuant analysis method, which abandons background data for many years by using the influence of tidal fluctuations to obtain incremental changes in radiation. The results demonstrate that the increase in OLR data identified via the background field analysis method was uncertain. In the time distribution, the occurrence time of anomalies is isolated and not continuous. In the spatial distribution, many OLR enhancement areas occurred multiple times in the non-seismic and remote seismic-related fault structure areas. In contrast, through the tidal force fluctuant analysis method a clear and consecutive OLR anomaly emerged in the seismogenic cycle of the tidal force. It corresponded with the tidal force through a unique evolution: increased-earthquake-shrink around the epicentre, consistent with the change in the law of thermal radiation during the rock-breaking process under stress, and clearly related to the earthquake's seismic tectonic stress change. It is proven that the tidal force of a celestial body may trigger an earthquake when the tectonic stress reaches its critical breaking point, and when the triggering action is a continuous rather than brief one-shot process. The in-situ stress state is key. The OLR anomaly was the physical performance of underlying surface radiation from the change in seismic tectonic stress.

Spatial-Temporal Mode Analysis and Prediction of Outgoing Longwave Radiation over China in 2002–2021 Based on Atmospheric Infrared Sounder Data

“…Among some outstanding authors in the world recently, the research on OLR mostly focuses on the study of OLR anomalies before and after earthquakes, and the method of useful background field analysis focuses on the increment of the multi-year average value of OLR data [23]. Some researchers studied whether the OLR data is abnormal before the earthquake nucleation in the seismically active area to determine whether the earthquake is nucleated [24], and some researchers study whether the OLR data will have an impact on the ionosphere disturbance before the earthquake and the correlation with some parameter changes, etc.…”

Employing Remote Sensing, Data Communication Networks, AI, and Optimization Methodologies in Seismology

“…In [28], the approach of background field analysis has been employed. That model concentrated on statistically processing radiation the data's worth and the tidal force fluctuant analysis approach, which uses the impact of tidal oscillations to get small changes in radiation after abandoning baseline data for a long time, was both utilized for outgoing longwave radiation data aiming at observing anomalies before and after six EQs.…”

Study of the OLR Anomalies before the 2023 Turkey M7.8 Earthquake

“…At the same time, due to the uncertainty of the selection time (5 years, 10 years, etc. ), the different background fields will present different results [29][30][31].…”

“…Outgoing long-wave radiation (OLR) represents the energy density of electromagnetic waves emitted into outer space via Earth's atmospheric system, and the radiation physical quantity most directly reflects the underlying surface properties and energy variation parameters. Moreover, its band (10.5-12.5 µm) is concentrated in the atmospheric window and minimally interferes with clouds [31]. Therefore, OLR data were selected for this research.…”