Earthquake rupture stalled by a subducting fracture zone
D P Robinson1, S Das, A B Watts
1Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR, UK. David.Robinson@earth.ox.ac.uk
Science (New York, N.Y.)
|May 27, 2006
Summary
The 2001 Peru earthquake
Area of Science:
- Geophysics
- Seismology
- Tectonics
Background:
- The 2001 Peru earthquake (Mw 8.4) provides a unique case study for understanding earthquake rupture dynamics.
- Subduction zone earthquakes are major seismic hazards, and their rupture behavior is complex.
Purpose of the Study:
- To investigate the role of a fault barrier in controlling the rupture propagation of the 2001 Peru earthquake.
- To analyze the characteristics of the barrier and its interaction with the earthquake rupture front.
Main Methods:
- Analysis of seismic data to map rupture propagation.
- Characterization of fault zone properties and seismic activity.
- Correlation of rupture dynamics with geological features.
Main Results:
- Rupture propagated ~70 km before encountering a 6000 km² fault barrier.
- The barrier delayed rupture for ~30 seconds and then ruptured.
- The barrier exhibited lower rupture speed, slip, and aftershock density compared to surrounding areas.
Conclusions:
- A fracture zone on the subducting plate likely acted as a significant barrier to rupture.
- Barrier rupture coincided with the main energy release, influencing the earthquake's overall size and duration.
- Understanding such barriers is crucial for seismic hazard assessment in subduction zones.
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