Earth, Atmosphere & Environment Sciences
Title : | Ionospheric imagery of earthquake source region using the Co-seismic Ionospheric Perturbations (CIPs) |
Area of research : | Earth, Atmosphere & Environment Sciences |
Principal Investigator : | Dr. Dhanya Thomas, CSIR Fourth Paradigm Institute |
Timeline Start Year : | 2022 |
Timeline End Year : | 2024 |
Contact info : | dhanyathomas999@gmail.com |
Details
Executive Summary : | During the occurrence of an earthquake, part of the released energy (~10-4 to 10-5 %) transfer to the surrounding atmosphere in the form of different atmospheric wave. These atmospheric waves further propagate upward with increasing amplitude and redistribute the background electron density at ionospheric altitudes. These electron density perturbations are generally known as Co-seismic Ionospheric perturbations (CIPs). The spatial and temporal characteristics of the CIPs has been investigated extensively in the past, specially using the Global Positioning System (GPS). The GPS stands exceptional in ionospheric studies in terms of its global coverage and temporal resolution. However, due to the integrated effect of the GPS-TEC, the altitudinal information of the CIPs from the GPS-TEC was unknown so far. To overcome this limitation, by focusing on the observations of early arrivals of CIPs during the Mw 7.4 Saniku -Oki earthquake, Thomas et al., (2018) have proposed a method to estimate the detection altitude of CIPs from GPS- TEC. Further, using this method Bagiya et al., (2020) have delineated for the first time, the individual seismic sources which are responsible for the observed CIPs within the 60s of the rupture during the Mw 9.0 Tohoku-oki earthquake. In addition, they could also derive the rupture extent by projecting the CIP distribution to their actual detection altitudes. Knowledge about the co-seismic crustal uplifts and rupture characteristics are very important for understanding the severity of the earthquake and also it is a major factor in tsunami forecasting modelling. Therefore, our main objective of the proposed study is to estimate the earthquake source characteristics by focusing on the arrival time and amplitude characteristics of CIPs. Hence, in the proposed study we will be selecting the earthquakes with specific source characteristics. Further, the effectiveness of the proposed method used in Thomas et al., (2018) will be examined in different source scenario. Also, we will be using the Spatio-Periodic Leveling Algorithm (SPLA) (Shimna K and Vijayan M.S.M., 2020; Vijayan M.S.M and Shimna K., 2021) in order to make use the very low elevations satellites in ionospheric imagery of seismic sources, which are generally excluded due to its elevation dependent errors. This will be useful specially for the offshore earthquakes where the stations are far away from the source region and thus the low elevation satellites become indispensable. |
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