geologic hazards

1
geologic hazards space geodesy

• part 1 Introduction

2
thanks

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

3
Geodesy
measuring the shape of the earth
4
and measuring changes
5
Many applications
6
From planetary physics
7
to Earth structure
8
to surface monitoring
9
What changes in the shape of the earth are
associated with tsunamis?
10
What causes tsunamis?
11
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

12
Before events
13
Before events
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.
14
Before events
15
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
16
During events
17
During events
18
During events
19
During events
Courtesy of Space Imaging and USGS CRSSP
20
So how can GPS help?
21
So how can GPS help?
22
So how can GPS help?
23
So how can GPS help?
24
So how can GPS help?
O. Konca, Caltech