1994 Bolivian Earthquake

Eric Kiser

1994 Bolivian Earthquake

• Moment Magnitude (Mw): 8.3

• Epicenter: 13.84°S and 67.55 °W

• Depth: 631km

Outline

• Rupture Characteristics

• Comparison with other Deep Earthquakes

• Tectonics

Silver et al., 1995

Directivity Analysis

Silver et al., 1995

Silver et al., 1995

Silver et al., 1995

• 30km by 50km Rupture Plane

• 40s Duration

• 1.25 km/s Velocity

• Rupture plane is too large

Other Rupture Properties

• No Isotropic Component (Okal, 1996)

• Friction melting (Kanamori et al, 1998)– Efficiency: 0.036– Non-Radiated Energy: 1.4x1018 J– 52,000°C Temperature Increase – Slow Rupture Velocity and Large Slip

Differences in the 1994 Bolivia and Tonga Earthquakes

Wiens and McGuire, 1995

Tonga Earthquake

Bolivia Earthquake

Tinker et al., 1995

Tectonic Setting

Kirby et al., 1995

Tectonic Setting

Kirby et al., 1995

Tectonic Setting

Kirby et al., 1995

Kirby et al., 1995

• Kinks from compression

• Kinks meet resistance at the lower mantle

• Slab Thickening

Summary

• Deepest earthquake ever recorded

• Rupture extent, no isotropic component, and seismic efficiency have important implications for deep earthquake mechanisms

• The majority of deep earthquakes may not exhibit these rupture characteristics