VOLCANIC HAZARDS ASSESSMENT. Human-based Data Sources Geochemical Data Geophysical Data. ACTIVE vs. EXTINCT VOLCANOES. Historians say: Active volcanoes are those that are erupting or showing some activity now.
Human-based Data Sources
Top: visual spectrum shows nothing new
Bottom: Interferogram measures areas
of differential change due to ground
swelling upward. Maximum displacement
is in center and pattern is concentric,
suggesting a pending volcanic eruption
There are 33 active volcanoes in the US
Most are at convergent plate boundaries in Alaska and N. California, Oregon, and Washington. These are all stratovolcanoes, which are the most dangerous in terms of explosive activity.
Some are on or near hotspots: Hawaii’s volcanoes, and Yellowstone
Some are former CPB: Central and Southern California
The remainder are on a failed rift (former divergent plate boundary): Arizona, New Mexico
Ash injected into
around the world
for up to 3 years
Lava and slope collapse produced a tsunami
up to 40m high.
-Killed 36,000 people in SE Asia
-Effects of Tsunami felt 7000 miles away
Ash and gases produced global cooling
that lasted 3 years