Geomorphic Comparison
Geomorphic
of Volcanoes on Earth and Mars: Implications for Plate Tectonics for Liz Roberts
University of Hawai`i at
University
Hawai at
Mānoa
Arkansas-Oklahoma
Ok
Center for Space and
Planetary Sciences
Planetary
July 29, 2004
Fayetteville, Arkansas
1
About this Presentation
Volcanoes are asymmetric in shape in map view and airborne and spaceborne imagery is utilized for measuring their circular spaceborne imager symmetry symmetry
Shield volcanoes are more symmetric than stratovolcanoes stratovolcanoes possibly due to the the hot spot being in a fixed position relative ive to the overriding plate to Volcanoes in different tectonic regions are examined to assess possible influences of tectonics on their geomorphologies possible Terrestrial volcanoes can be compared to Martian volcanoes to assess possible tectonic control of edifice evolution assess A larger database of volcanic asymmetry data is needed before further analysis of tectonic influences on terrestrial and Martian further an volcanoes volcanoes
2
Parallel to flight path
Perpendicular to flight path
Longest length of edifice
Perpendicular to the longest length
Direction of flight
6
Measuring the Volcanoes
Galapagos Islands
Isabela Island
Alcedo
Cerro
Azul
Sierra Negra
7
Measuring the Volcanoes
8
Measuring the Volcanoes
Philippines
SIR-A
Perp
(cm)
Long
(cm)
Perp to to Long
(cm)
(cm)
Ratio
Ratio
a
Ratio
Ratio
b
Sym
Sym
(%)
(%)
Volcano
Location
Para
(cm)
Ragang
Philippines
7.650
8.900
9.200
6.65
.8596
0.7228
84.09
Kalatungan
Philippines
6.325
6.250
9.300
4.2
1.012
.4516
44.63
9
Comparing to Plate Tectonics
Do plate tectonics influence the asymmetry of a volcano? asymmetry • 2 Different Tectonic Regions
Volcanoes in the Galapagos are formed from a “hot spot”; interplate tectonics interplate • Shield volcanoes
All other volcanoes in this study are formed from an ocean-ocean convergent boundaries from • Stratovolcanoes
10
10
Comparing to Plate Tectonics
The shield volcanoes
The
appear to be more symmetric than the stratovolcanoes!!! stratovolcanoes
11
11
Comparing to Plate Tectonics
Volcano
Location
Tectonic
Tectonic
setting* setting* Symmetry %
Alcedo
Galapagos
I
94.43
Cerro Azul
Cerro Az
Galapagos
I
96.66
Sierra Negra
Sierra Negra
Galapagos
I
71.72
Soufriere
St. Vincent
CM
85.95
Patuha
Java
CM
53.04
Tangkubanparahu
Java
CM
76.65
Ragang
Philippines
CM
84.09
Kalatungan
Philippines
CM
44.63
Matutum
Philippines
CM
56.57
* I = Interplate, CM = Convergent Margin
Interplate
