Thursday, November 3, 2011, 16:00
WHGA/001
E. Casarotti, INGV, Italy
Abstract:
During the last years, the energy released by the earthquakes has caused directly and indirectly
hundreds of thousands of casualties and trillions of dollars in damages.
In our digital age, images and video widespread the shock for the dramatic destruction
produced by these events, in particular the 2004 M9.1 Sumatra and the recent 2011 M9.0
Japan Earthquake. Media around the world have also reported scientific research and
comments. In this context, one of the more recurrent news is the theoretical effect of the seismic
deformation on the rotation and gravity of the Earth. Due to the action of various internal
geophysical processes the Earth rotates about an axis not aligned with its figure axis; this
induces the Planet to wobble as it rotates. The Earth wobbles over a broad range of frequencies
in response to a variety of forcing actions. The predominant mechanisms were found to be
concerned with the periodical redistribution of atmospheric, oceanic and hydrologic masses.
Nevertheless, the most energetic earthquakes produce enough deformation to change the
inertia tensor of the Earth and consequently its rotation.
I present a review of the result in this field ranging the last 20 years and some of the recent
improvement in seismology.