1. Volcanoes and Society Notes

2. Where are most of Earth’s volcanoes?
Pacific Ring of Fire
75% of Earth’s active and dormant volcanoes
Volcanism is mostly focused at plate margins OR hot spots
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?

3. Where are most of Earth’s volcanoes?
Pacific Ring of Fire stretches along east Asia, across Alaskan Islands, and along the coast of the Americas
US contains only about 10% of all active volcanoes
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?

4. How do volcanoes affect society?
There are thought to be about 600 million people living close enough to active volcanoes to be affected when they erupt.
Casualties from volcanic eruptions have been modest (around 300,000 in the last 200 years) compared to other geohazards, but socioeconomic losses and disruption can be considerable.
The modern globalized world is vulnerable to very large volcanic events, making the study of return periods, environmental effects, and consequences a key goal of volcanology.
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?

5. What type of risks do volcanoes pose?
Flooding
Due to rise in water level/glacial melting
Destroys structures, obstructs traffic (air traffic impeded by ash)
Global Climate Impact
Sulfur clouds make Earth’s atmosphere more reflective, cooling the planet
Interferes with crop production
Property Damage
ex:
Insurance is not widely available and is costly
why?
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?

6. How do we analyze disaster risk?
Around the world, disasters occurs each day. Sometimes the impacts are felt locally, other times, the event reaches across state and national boundaries.
Globally, the number of natural disasters has increased 4X during the past 3 decades—from about 120/year during the 1980s to roughly 500/year now.  These disasters exert a uneven impact on the world’s poorest and most vulnerable individuals.
why?
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?

7. How do we analyze disaster risk?
To calculate the risk of a natural disaster occurrence, we have to have information about past occurrences.
This helps us estimate return periods and better prepare and manage future events.
Disaster risk can be calculated by dividing the number of past events by the time period over which they occurred.
Example:
This map shows the margins of the Pacific tectonic plate and surrounding region. The red dots show the location of active volcanism. Notice how the majority of the volcanism is focused in lines along the plate boundaries? For this region this area is known as the “Pacific Ring of Fire”.
But why are all of the volcanoes located at the plate margins?