Numerical Modeling of Coseismic Tropospheric Disturbances Arising from the Unstable Acoustic Gravity Wave Energetics

Esfhan A Kherani,Eurico R De Paula,Saul A Sanchez

doi:10.3390/atmos12060765

Abstract

Numerous recent studies report the Coseismic Tropospheric Disturbances (CTDs) during large earthquakes. Their presence suggests the importance of atmospheric seismology in a possible earthquake forecasting scenario. The origin mechanism and associated energetics of CTDs are not well understood though the observations associate them with the atmospheric waves. We present the numerical modeling of coupled dynamics of Gravity waves (GWs) and convective instability (CI) in the dry troposphere that produces the CTDs, in the form of pressure disturbances, of observed magnitudes. The study reveals the altitude and epicentral distribution of CTDs and elaborates the relative role of GWs and CI in the generation and intensification of CTDs. The study finds that mega and strong earthquakes disturb the troposphere to a similar level as the severe meteorological weather.

Highlights

National Institute for Space Research, Av. dos Astronautas, 1758, Sao Jose dos Campos 12227010, Brazil; Abstract: Numerous recent studies report the Coseismic Tropospheric Disturbances (CTDs) during large earthquakes
Several studies in recent years report the detections of Coseismic Tropospheric Disturbances (CTDs) during strong earthquakes of magnitudes larger than 7 [2,3]
The present study investigates the coupled dynamics of gravity waves and convective instability and their role in the formation of coseismic tropospheric disturbances (CTDs) and Tropospheric Range Delay (TRD)

Summary

Introduction

Several studies in recent years report the detections of Coseismic Tropospheric Disturbances (CTDs) during strong earthquakes of magnitudes larger than 7 [2,3] These CTDs are observed as tropospheric delay in the radio signal, as registered from the GNSS receivers scattered across the epicenter [4,5]. Mikumo (1968) [7] invoked energetics of Acoustic Gravity Waves (AGWs) to explain the detection of coseismic atmospheric disturbances at the ground during the great Alaskan earthquake of magnitude 9. He showed that most of the observed features of ground pressure disturbances are the manifestation of the AGWs of seismic origin. The presence of coseismic pressure disturbances at the long epicentral distance of about 6000 km is owing to the robust energetics of AGWs in the reflecting layers [2]

Results

Discussion

Conclusion