Presentation is loading. Please wait.

Presentation is loading. Please wait.

What caused Mt. St. Helen’s to erupt?

Similar presentations

Presentation on theme: "What caused Mt. St. Helen’s to erupt?"— Presentation transcript:

1 What caused Mt. St. Helen’s to erupt?
Volcanic Activity What caused Mt. St. Helen’s to erupt?

2 Where do Volcanoes Occur?

3 Where do volcanoes occur?
Along convergent boundaries above subduction zones Ring of Fire Along divergent boundaries at mid-ocean ridges

4 Hot Spots Hot Spots are unusually hot regions of Earth’s mantle where plumes of magma rise to surface Located away from plate boundaries Example: Hawaii

5 Volcano Status Active Erupts Regularly
Lifetime can span months to millions of years Can be currently erupting or showing signs of unrest (earthquakes, emitting gas) Ex: Mt. St. Helens

6 Extinct Dormant Unlikely to erupt again No magma/lava supply
Ex: Hawaiian Islands not over hot spot Dormant Erupted in past but is now quiet *Difficult to determine status of volcanoes*

7 Effects of Volcanoes Volcanoes emit water vapor, carbon dioxide, and sulfur dioxide into the air Gases are suspended in atmosphere and block radiation from sun Global temperatures can be affected Health issues for humans (Respiratory) Pyroclastic flows, tephra, lahars (hot mud flow)

8 Volcano Predictions? Volcanologists study deposits left from previous eruptions Warning Signs: earthquakes activity and gas emissions Seismometers measure EQs and correlation spectrometers measure SO2 levels

9 Volcano Safety Structural support – walls, supportive buildings
Evacuation procedures Communication between scientists and public

10 Volcanoes in our Solar System
Volcanoes may have been present in the history of other planets Mars, Venus Volcanoes are active on Jupiter's moon, Io

Download ppt "What caused Mt. St. Helen’s to erupt?"

Similar presentations

Ads by Google