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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
QuickTime™ and aMPEG-4 Video decompressor
are needed to see this picture.
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?
What causes tsunamis?
• Fault slip caused the sea floor to deform (4-5 meters up, and 10-11 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 Ocean Sumatra
WEST EAST
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, itgets caught for hundreds of years and then the stored stressis released in a big earthquake.
Before events
Before events
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
During events
During events
During events
Courtesy of Space Imaging and USGS CRSSP
So how can GPS help?
So how can GPS help?
So how can GPS help?
So how can GPS help?
So how can GPS help?
O. Konca,Caltech