Archive for April, 2010

Top 10 Facts to Know About Stratovolcanoes

April 30th, 2010 -- Posted in Volcanoes | 19 Comments »

Mount Fuji, a stratovolcano

Of the four types of volcanoes, let’s take a close look at the dramatic stratovolcano.

1. Frequent pyroclastic eruptions give stratovolcanoes their towering cone shape.

2. Eruptions can originate from the summit or flank vents.

3. Subduction-zone stratovolcanoes, like Mount St. Helens, typically erupt with explosive force.

4. Some of the most powerful and destructive volcanoes in human history have been stratovolcanoes.

5. Stratovolcanoes are the most common type of volcano.

6. Of Earth’s 1,511 volcanoes known to have erupted in the past 10,000 years, 699 are stratovolcanoes.

7. Some of the most beautiful mountains in the world are stratovolcanoes, including Mount Rainer in Washington, Mount Fuji in Japan, and Kamchatka in Russia.

8. Magma, from deep in the Earth’s crust, travels through a conduit within the stratovolcano, which becomes lava when it erupts.

9. Between eruptions stratovolcanoes can be quiet for tens of thousands of years, seeming extinct.

10. Many cataclysmic eruptions throughout history were stratovolcanoes, including Mount Pelee in Martinique, El Chichon in Mexico, Mount Vesuvius in Italy, and Krakatoa in Indonesia, causing catastrophic loss of life.

Iceland Volcano Continues to Spew Lava

April 29th, 2010 -- Posted in Volcanoes | No Comments »


Eyjafjallajökull is one of the largest volcanoes in Iceland. Only three eruptions are known at Eyjafjallajökull in historical times, one in 920 A.D., another in 1612 AD, and the most recent in 1821. But on March 20, 2010 Eyjafjallajökull exploded back to life.

According to scientists at the Institute of Earth Sciences Nordic Volcanological Center, today the eruption in Eyjafjallajökull has a continuing discharge of meltwater from Gigjokull Glacier due to ice melt caused by the volcano. Booming sounds have been reported as far as 32 km from the eruption site. While ash and steam rise to an elevation of 3.6 km (12,000 ft), ejected lava reached heights of 660 feet.  Would we expect anything less from an active stratovolcano?

Scientists are monitoring Eyjafjallajökull with radar observations, GPS measurements, satellite images, seismic monitors, river gauges, aerial observations, and geologist’s inspections of tephra. Tephra is the term for materials of all types and sizes thrown into the air by a volcanic eruption.

Do you live in a Danger Zone?

April 28th, 2010 -- Posted in Earthquakes | No Comments »

Everyone knows California is earthquake country.  But if you think living outside of California means you’re safe from experiencing an earthquake, think again. The U.S. Geological Survey provides earthquake hazard maps that reveal the true picture of danger zones in the United States. The bright red color indicates a high probability level of ground shaking.

Are you surprised to see that vivid red covering much of South Carolina? That’s due to offshore faults that could potentially shake up the Palmetto State. What about Tennessee, Missouri and Arkansas?  This New Madrid Seismic Zone is of major concern to geologists due to the possibility of several large earthquakes in a region of the country not prepared for such events.

While I expected Washington and Oregon to join California on the red zone map, Wyoming and Utah are a surprise to me.  The USGS updates their maps periodically to include new faults discovered, ground-motion model studies, and updated fault geometry.

Welcome to Fierce Planet

April 28th, 2010 -- Posted in Earthquakes, Volcanoes | No Comments »

Fierce Planet is my launch into the blogging world.  This site will document the planet’s mood swings, attitudes, and actions.  I will notify readers of interesting facts and events.  We’ll talk about earthquakes, volcanoes, tsunamis and more!  My blog will pay homage to the powerful planet we inhabit.  At any moment nature can wreck havoc on our lives.  Earth’s power can devastate us; can wipe out an entire civilization. Indeed earthly catastrophes have wiped out many an empire and many an ecosystem.

Earth is evolving as it always has.  We’ll survive as long as the planet intends for mankind to survive.  I know I’m not the only one fascinated by the awesome forces at work below the surface.  Don’t wait until the next disaster to learn about Mother Nature.  Visit this site often and you’ll be an expert when the next catastrophe strikes. Join the discussion. Leave comments. Ask questions. We’ll learn together!