Ionospheric Earthquake Precursors
- People all over the world have experienced and reported anomalies in the observable atmosphere and in the behavior of animals living close to humans before and during the severe earthquakes. Although most of these observations and reports have been considered as ‘old wives’ tales’ in the last century, in the last twenty years, scientists started to investigate the reported phenomena before the earthquakes with increased attention.
- Increased observations of the ionosphere with the ionosondes, both top-side and bottom-side, before and during the earthquakes suggest that there are several disturbances and variations in the ionosphere especially in the critical frequency, ion temperatures and Total Electron Content (TEC) distributions. Therefore, many scientists all over the world suspect that the major cause of the disturbance of the ionosphere during and before the seismic activity might be due to the variation in the electromagnetic (EM) field and the chemical composition of the ionosphere.
- There have been various theories that try to explain EM anomalies associated with pre-seismic activity, and several theories have been formulated to explain their causes. Yet, ionosphere is a layer of the atmosphere which is an integral part of whole geomagnetic and geological framework. Therefore, although evidence indicates that there has been variations observed in the VLF, LF and HF signals, magnetic field of the earth and in the electric field, scientists are far from forming a unified theory that would explain the mechanism and cause of the disturbance in the layers of atmosphere.
- The Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) model due to seismicity is one of the most recent theories built on the novel concept that the period prior to an earthquake is accompanied by gas emanation, change of air conductivity, enhancement of surface temperature, locally generated electro-static field that can be easily detected by ground-based or remote sensing satellite sensors before a tectonic energy release.
- IONOLAB group will investigate possible earthquake precursors by observing variations in single station TEC, TEC maps and Computerized Ionospheric Tomography (CIT) images of electron density in the TUBITAK 105E171 project.