Geomagnetic Disturbances During the Maule (2010) Tsunami Detected by Four Spatiotemporal Methods

Separating tsunamigenic variations in geomagnetic field measurements in the presence of more dominant magnetic variations by magnetospheric and ionospheric currents is a challenging task. The purpose of this article is to survey the tsunamigenic variations in the vertical component (Z) and the horizontal component (H) of the geomagnetic field using four spatiotemporal methods. Spatiotemporal analysis has shown enormous potential and efficiency in retrieving tsunamigenic contributions from geomagnetic field measurements. We select the Maule (2010) tsunami event on the west coast of Chile and examine the geomagnetic measurements from 13 ground magnetometers scattered in the Pacific Ocean covering a wide area from Chile, crossing the Pacific Ocean to Japan. The tsunamigenic magnetic disturbances are possibly due to two types of contributions, one arising from direct ocean motion and the other from atmospheric motion, both associated with tsunami forcing. Moreover, even though the tsunami waves decrease considerably with increasing epicentral distance, the tsunamigenic contributions are retrieved from a magnetic observatory in Australia (similar to 13,000 km radial distance from the epicenter). These results suggest that various types of tsunamigenic disturbances can be identified well from the integrated analysis framework presented in this work. (AU)