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Falk Amelung RSMAS - University of Miami
Sang-Ho YunStanford University
Thomas Walternow at GFZ Potsdam
Asta MikliusHawaii Volcano Observatory
Pinatubo 1991
Luzon M7.8earthquake
100 km
Mount Pinatuboerupted 9 monthsafter earthquake
Bautista et al., 98
Did the earthquake trigger the eruption, and how ?
Karymksy 1996
Static stress changes may explain the eruption !
Static stress changes due to earthquake
Galapagos Islands
Fernandina
Isabela Island
Fernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
Jonsson et al.,
FernandinaEruptions in1995,13 May 2005
Galapagos Islands
Fernandina
Isabela Island
Fernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
Jonsson et al.,
Static stress changesFernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
Modelling of changes in the stress field along caldera-bounding “rift zone”
Static stress changesFernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
clampingunclamping
Normal stress
3D view
Static stress changesFernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
clampingunclamping
Normal stress
3D view
Conclusion:2005 dike intruded in area un-clamped by the 1995 dike !
unclamping
Fernandina1992-1998 ERS interferog
1995 radial dike
2005 circum-ferential dike
clampingunclamping
unclamping
Fernandina and Isabela Islands - Ground DeformationSierra Negra volcano
0
trapdoor faulting in 1998
Sill at 2 km depth
Sierra Negra volcano
ERS interferograms
Fernandina and Isabela Islands - Ground Deformation0
trapdoor faulting in spring 200
Sierra Negra volcano
Envisat interferograms
Sierra Negra volcano0
north-south cross-section
eruption 22 Oct 2005 trapdoor faulting in spring 20
Envisat interferograms
eruptions 1979, 2005
?, 1998, 2005
Conclusion:2005 eruption site consistent with propagating sill model
sill propagation model
Simulation: Sang-ho Yun
The Hawaiian Volcanoes
Mauna Loa: eruptions in 1950, 1984Kilauea: continuous eruption since 1983
Photos: HVO
Mauna Loa volcano, Hawaii
Inflation since May 2002~ 7 cm/yr extension across caldera
ALEP
ELEP
Mauna Loa volcano, Hawaii2002-2003 Radarsat A3 interferogram
Stacked Interferograms
Ascending,Beam 3
Mauna Loa volcano, Hawaii
stack of 4 Interferogramsascending S3
Opening along Rift Zone
- maximum dike inflation south of caldera beneath summit resedeep rift intrusion, 0.25 m/yr openingmagma chamber, 4.5 km depth, 1-1.3 km radius
Kinematic model Dynamic model
variable magma excess pressure, point source,
halfspace
uniform magma excess pressure, finite source, topography (Williams & Wadge
method)
Mauna Loa magma plumbing system
Opening along Rift Zone
- maximum dike inflation south of caldera beneath summit rese
deep rift intrusion magma chamber 1-1.3 km radius
Dynamic model
uniform magma excess pressure, finite source, topography (Williams & Wadge
method)
Mauna Loa magma plumbing system
Opening along Rift Zone
- maximum dike inflation south of caldera beneath summit reseInflation of magma plumbing System encourages decollement faulting !
Status stress changes
Conclusions
Fernandina: stress-transfer model predict location of
2005 circumferential dikeSierra Negra: sill propagation model pre
2005 eruptive dike
Mauna Loa: decollement slip consistent witchanges due to the inflation of
model magmatic sy
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