Monitoring Remote VolcanoesBy Deformation

1992-1999

Courtesy of Amelung, Jonsson, Zebker, and Segall (Nature, 2000)

Causes of Deflation

• Submarine eruption– Should cause deformation signal

• Lateral intrusion– Should cause deformation signal

• Vesicle segregation– Should cause densification = gravity signal

• Drainback

Continuous Network

Deflation

Accelerating Inflation

October 20, 2005 Eruption

Decelerating Inflation

Cerro Azul Transient

October 20, 2005 Eruption

April 16, 2005 Trap Door Fault

Accelerating Inflation

Trapdoor Fault

GV06

October 23, 2005

Eruption

Continuous Network

2005Lava

Decelerating Recovery

Before AfterUpper balloon will inflate at decelerating rates

Q = r P

4

8L

Poiselle Flow

Cerro Azul Transient

Cerro Azul Event

Eruption End

Eruption Start

2009 Model

+40.1 cm/y

Inflation

Deflation

Eruption

Conclusions

• Intrusion is forming by unsteady but continual supply of magma.

• Feedback between faulting of the roof, eruption, and resupply.

• Feedback between pressure, volume, and degassing.

• Dikes do not form along faults!

Fernandina

Sierra Negra

Extremely remote: Largest wilderness tropical island in the world

Inhabited and developed

Green = Observed

Red = Inflation by InSAR

Blue = Coeruption

2002-2006 GPS

Questions

• What causes the fluctuation in magma supply?

• Why do dikes form on the hinge, not the fault?

• What controls faulting vs. eruption?• Why didn’t faulting relieve pressure?• How does the feedback between pressure,

volatiles, and deformation work?