Investigation of the statistical and spatiotemporal pre-seismic ionospheric disturbances associated with the 2023 Mindanao earthquake (Mw 7.6), Philippines

This present research explores the ionospheric Total Electron Content (TEC) irregularities as potential precursors to earthquakes, specifically examining the seismic event that occurred on December 2, 2023, in Mindanao, Philippines, registering a magnitude of 7.6 Mw. By conducting a thorough examination of space weather parameters and TEC fluctuations from various CORS stations lying within the earthquake preparation zone, consistent patterns in ionospheric behavior preceding seismic occurrences were discerned. Substantial negative TEC anomalies were detected near the epicenter of the earthquake, suggesting a coordinated response within the ionosphere. Moreover, correlation and covariance analyses were utilized to gain insights into the associations among TEC measurements from signals of different GPS satellites (identified by their PRNs), enriching our comprehension of collective ionospheric dynamics. Spatial and temporal interpolation techniques further emphasized a distinct anomaly zone in the vicinity of the epicenter on November 14, 2023, a noteworthy anomaly day. Additionally, analyses involving Histogram and Probability Density Function (PDF) unveiled a clustering of absolute vTEC values around 40 TECU during the anomaly period, underscoring their potential value as early warnings for impending seismic event. A comprehensive examination of TEC data throughout 2023 revealed an 88% success rate in detecting anomalies preceding earthquakes of magnitude 5 and above. These outcomes contribute to refining methodologies for detecting earthquake precursors, thereby improving preparedness measures for seismic occurrences in vulnerable regions, such as the Philippines.