GEOL 5903 Seminar: Daniel Mutton

November 26, 2019 (12:00 pm - 1:00 pm)


26 November 2019

GEOL 5903 Seminar: Daniel Mutton
Title: "Do Pre-seismic Ionospheric Precursor Signals Exist?"
Location and Time: Huggins Science Hall, Room 336, 12:00 p.m.
Abstract:
Global navigational satellite systems (GNSS) technology has been rapidly advancing since their development in 1978. Originally, GNSS were geospatial positioning systems which allowed for high precision positioning with applications to navigation. However, GNSS have more recently been used to observe ionospheric total electron content (TEC). Traditionally TECs are used to monitor the magnitude of geomagnetic storms and the strength of electromagnetic waves that travel through the atmosphere. Changes in paths and velocity of radio waves in the atmosphere has a huge impact on the accuracy of GNSS systems, causing up to tens of metres of error in position calculations.  TEC can be used for earthquake monitoring because of the existence of co-seismic ionospheric disturbances (CIDs). CIDs appear shortly after an earthquake and were first detected with GNSS in 1995. The CIDs are caused by various forms of waves triggered by earthquakes; these waves excite the electrons in the atmosphere which takes the form of an observable change in the TEC. While an increase in the TEC post-seismic event is relatively uncontroversial, studies have reported possible TEC enhancement preceding earthquakes by up to several hours These pre-seismic TEC enhancements are not widely accepted, and critics generally fall into two categories: those who doubt the existence of CIDs and changes in TEC due to seismic activity itself and attribute them to artifacts of the hardware, and those who doubt the significance of the change in TEC among the naturally variability of space weather.


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