Terrestrial outgoing infrared radiation as an indicator of seismic activity

Abstract: The analysis of satellite thermal images of the Earth's surface within the spectral range of 10.5-11.3 mkm has shown that over some linear structures of the Middle-Asian seismically active region there is observed a stable in time and space increasing intensity of the outgoing radiation flux as compared to contiguous blocks. A retrospective analysis of a continuous series of observations of the outgoing IR radiation flux has shown that in certain individual zones of some major tectonic dislocations there appear from time to time positive anomalies of IR radiation, for instance at the point of intersection of the Talasso-Ferghana and Tamdy-Tokrauss faults. These anomalies last from 2 to 10 days. The spontaneous anomalies are characterized by a pulsating variation of area. The space confinement and duration of these anomalies permit distinguishing theme noise anomalies caused by meteorological factors. The time of the appearance of these anomalies coincides with the activation of faults over which there has been detected an increase of the outgoing IR radiation flux. In 1984 the majority of crustal earthquakes, of a magnitude over 4, in the Tien Shan were accompanied by the appearance of a positive anomaly of the IR radiation at the point of the intersection of the faults. The area of anomalies was n*10000 km2. The most outstanding example of such activization is the Ghazli earthquake of 19.03.1984 M7.2. At the point of the intersection of the Tamdy-Tokrauss and Talasso- Ferghana faults there was detected on March 11 a positive anomaly of the outgoing IR radiation flux of exceptional intensity and enormous area (about 100 thousand km2). The subsequent earthquakes in the zone of the Tamdy-Tokrauss fault in the summer of 1984 of the magnitudes from 4.3 to 5.3 were also preceded by the appearance of a positive anomaly of the outgoing IR radiation at the point of intersection of the faults.

• The paper demonstrates that IR radiation flux anomalies appear along key fault lines as precursors to seismic events.
• It employs satellite imagery in the 10.5–11.3 μm range to correlate IR anomalies with earthquakes of magnitudes 4.3 to 7.2, notably before the 1984 Ghazli event.
• The findings imply that monitoring gaseous emissions linked to seismic activity could strengthen earthquake prediction models and preparedness efforts.

Terrestrial Outgoing Infrared Radiation as an Indicator of Seismic Activity: An Overview

The paper "Terrestrial Outgoing Infrared Radiation as an Indicator of Seismic Activity" by Gorny et al. presents a detailed analysis connecting anomalies in terrestrial outgoing infrared (IR) radiation with seismic events. Utilizing satellite thermal imagery (STI) within the spectral range of 10.5-11.3 micrometers, the authors examine the Middle-Asian seismically active regions, particularly around key fault lines such as Kopet-Dagh and Talasso-Ferghana.

Key Findings

The researchers highlight the consistent increase in IR radiation flux over certain linear structures compared to adjacent blocks, providing significant information about seismic precursors. A retrospective study spanning several seismic events reveals positive anomalies in IR radiation prior to significant earthquakes. These anomalies, persisting from 2 to 10 days, emerge spatially confined, suggesting these are not noise but genuine precursors to seismic activity.

The 1984 Ghazli earthquake serves as a pivotal example. A remarkable IR anomaly was detected on March 11, eight days before the event, emphasizing the correlation between IR radiation anomalies and seismic occurrences. Subsequent earthquakes in this region further supported these findings, with noticeable IR anomalies preceding seismic events of magnitudes ranging from 4.3 to 7.2.

Mechanistic Insights

A critical discussion in the report concerns the origin of these IR anomalies. The authors propose that rather than stemming from the direct conversion of mechanical energy to thermal energy during earthquake maturation, the anomalies likely arise from increased atmospheric concentrations of gases such as H₂, CO₂, CH₄, which are known to emanate from seismically active faults and are linked to greenhouse effects. These concentrations can rise significantly during seismic events, leading to measurable increases in surface temperatures and corresponding IR anomalies.

The luminescence of gases in the IR range as an earthquake precursor is also considered, suggesting the complexities inherent in predicting seismic events using terrestrial IR radiation data.

Broader Implications

The implications of this study span both practical seismic monitoring and theoretical understanding of geophysical processes. The potential to use IR anomalies as a predictive tool for seismic events could vastly improve regional preparedness and response strategies. Furthermore, understanding the atmospheric and geophysical interactions that lead to these anomalies enhances the broader field of earthquake prediction research.

Conclusion and Future Considerations

This paper highlights the promise of terrestrial outgoing IR radiation as a valuable indicator in the field of earthquake prediction. Future research should focus on validating these findings across different geographies and further elucidating the mechanisms linking atmospheric phenomena to seismic activities. The development of robust models incorporating IR data could potentially advance the predictability of earthquakes, offering a valuable tool for mitigating the risks associated with seismic disasters.