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

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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