geologic hazards & space geodesy part 1: Introduction

thanks Ken Hudnut, USGS Roger Bilham, University of Colorado USAID, ADPC, USGS Thai National Disaster Warning Center Chulalongkorn University

Geodesy measuring the shape of the earth…

and measuring changes

Many applications

From planetary physics

to Earth structure

to surface monitoring

What changes in the shape of the earth are associated with tsunamis?

What causes tsunamis?

Fault slip caused the sea floor to deform (4-5 meters up, and meters to the west) This pushed the water and formed the tsunami Model by Dr. Chen Ji at Caltech, funded by USGS external research program

Before events

Indian OceanSumatra WESTEAST Where the India plate is pushed down beneath the Banda micro- plate, it is being SUBDUCTED. Where the two plates’ surfaces are sliding past each other, it gets caught for hundreds of years and then the stored stress is released in a big earthquake. Before events

Temporal variations do occur: –Clustering (e.g., Basin & Range, ECSZ, Asia) –Discrepant geological and geodetic rates –Sequences involving fault interaction (e.g., Joshua Tree - Landers - Big Bear - Hector Mine; Anatolian system, etc.) Implement robust research findings into hazard assessment Courtesy Anke Friedrich

During events

Courtesy of Space Imaging and USGS CRSSP

So how can GPS help?

O. Konca, Caltech