A mathematical model of lithosphere–atmosphere coupling for seismic events

Significant evidence of ionosphere disturbance in connection to intense seismic events have been detected since two decades. It is generally believed that the energy transfer can be due to Acoustic Gravity Waves (AGW) excited at ground level by the earthquakes. In spite of the statistical evidence of the detected perturbations, the coupling between lithosphere and atmosphere has not been so far properly explained by an accurate enough model. In this paper, for the first time, we show the result of an analytical-quantitative model that describes how the pressure and density disturbance is generated in the lower atmosphere by the ground motion associated to earthquakes. The direct comparison between observed and modelled vertical profiles of the atmospheric temperature shows the capability of the model to accurately reproduce, with an high statistical significance, the observed temperature fluctuations induced by strong earthquakes.

Visualizing Sporadic E using Aeronautical Navigation Signals at VHF Frequencies

<p class="Abstract" style="margin: 6pt 0cm 0cm; font-size: medium; font-family: &quot;Times New Roman&quot;, serif; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); text-align: justify;"><span lang="EN-US">To understand the dynamical properties of sporadic E layer (Es), we have developed a new method to visualize the two-dimensional spatial structure of Es by monitoring the occurrence of anomalous propagation of VHF waves used for aeronatucal navigation systems in combination with the electron density disturbance index ROTI, that is the Rate of Total Electron Content (TEC) Index obtained from ground-based GPS receivers. We introduce a case of strong Es layer which occurred for ~4 h during daytime of July 4, 2019. In this interval, we succeeded in imaging the structure of Es elongating more in the east-west direction and moving northward gradually. This result indicates that the combination of network observations of aeronautical navigation signals and GPS-TEC ROTI is capable of imaging the 2D structure of Es in a wide area including the sea surface, which enables us to discuss the dynamical characteristics and generation mechanism of Es.<br clear="all" style="break-before: page;" /><o:p></o:p></span></p>