Near‐ and far‐field tsunamigenic effects on the Z component of the geomagnetic field during the Japanese event, 2011

Abstract

AbstractIn this work, we examine the vertical component (Z) of the geomagnetic field observed by ground‐based observatories during the tsunami event which happened on 11 March 2011. For this event, we have selected nine magnetic observatories distributed along the tsunami passage, covering up to 3000 km epicentral distance. The traveltime diagram of the magnetic disturbances is constructed and compared with the simulated tsunami traveltime diagram. From this comparison, we identify the amplified magnetic disturbances appearing during the tsunami arrival in the vicinity of these observatories. Moreover, mean absolute percentage error map is constructed to examine the cross correlations among different observatories and the amplified disturbances are found to be highly correlated. These features suggest that the amplified disturbances are tsunamigenic in nature. These results are in confirmation with the previous near‐field studies, and they shed new insight into the tsunamigenic magnetic disturbances on near‐ and far‐field distances from the epicenter.