What does lava do? Why is lava so hot? (Mrs. Wood's 1st Grade Class, ages 5-6, Las Vegas, Nevada)

One useful byproduct of volcanic eruptions is to produce very rich, fertile soils on the flanks of volcanoes (and neighboring areas). This comes about through the process of weathering - the natural beak-down of the minerals in lava and volcanic ash and release of the nutrients. In turn, this encourages people to cultivate these areas - and it also puts these people in danger when volcanoes become active. Lava is hot because it is molten (liquid) rock. The temperature of lavas reaches 1100 degree centigrade.

How are volcanoes made? (Mrs. Wood's 1st Grade Class, ages 5-6, Las Vegas, Nevada)

The beautiful conical shapes of volcanoes result from many lava and ash deposits piling up around a volcanic vent or edifice.

How do they erupt? (Mrs. Wood's 1st Grade Class, ages 5-6, Las Vegas, Nevada)

Gas has a lot to do with the eruption of volcanoes (this is one of the prime objectives of our study). Lavas can become very 'frothy' - like shaking a fizzy drink - and the large volume of material (gas + lavas) spills out of the volcanoes.

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What is a volcano? (Brayan Suiter, age 8, Chula Vista, California)

A volcano is a vent in the crust of the earth (or other planet) from which hot or molten rock, steam, and ash emerge.

Though most volcanoes are mountains, most mountains are not volcanoes; why not? (Alex Wood, age 10, Las Vegas, Nevada)

Look around you. If you live in a part of the world where there are mountains but no volcanoes, you must be far from any subduction zones, spreading centers, or "hot spots." For example, if you live in the central or eastern United States, chances are you have never seen a volcano. If, on the other hand, you live in the Pacific Northwest, Alaska, or Hawaii, you are actually living close to (or even on top of!) a volcano. That is because the West Coast of North America is part of the Pacific Rim of Fire. If you live in the Mountain States, you are near one of the best known "hot spots" in the world: Yellowstone National Park. Though there are no volcanic mountains in Yellowstone, there is lots of volcanic activity, resulting in such dramatic features as Old Faithful geyser. In fact, Yellowstone lies at the active surface of a molten cauldron deep within the earth that once fed an immense volcano, now collapsed and referred to as a caldera.

Do volcanoes erupt all of the time?(Mini-imah Ali-Muslim, Plainfield NJ)

No, not all the time. The frequency of eruption is a very difficult parameter to quantify - but we can look at the eruption history (dating of deposits can help us gauge the frequency).

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I have been to the summit of Haleakala in Maui. When will be the next time Haleakala will erupt in Maui? (Justin Benjamin Satnick, Canyon View, San Diego, California, U.S.A)

Hi Justin,
Lucky you! (I've never been to Maui). Easy answer to your question: I don't know! Predicting volcanic and seismic activity is one of the most difficult tasks in volcanology. Haleakala last erupted in 1790 - just over 200 years ago and is likely to erupt again in the future (sometime!)

How long do volcanoes last? (Gerald, Walden III Middle School, Wisconsin)

Good question. In Hawaii the lifetimes of the volcanoes are about 1 million years maximum - as the movement of the Pacific Plate moves the volcano away from the underlying region of melting. In theory, subduction zone volcanoes could have a longer lifetime.

How many times does a volcano erupt in a year? (Stephanie, Walden III Middle School, Racine, Wisconsin)

There is always a volcano erupting somewhere - how frequent a particular volcano erupts is highly variable.

What is a petrologist? (Chelseak, Walden III Middle School, Racine, Wisconsin)

"Petro" means rock, therefore petrologist is someone who studies rocks.

Is lava blood? (Rose)

If you're a poet, maybe you could describe lava as the blood of the earth!

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When the magma hits the water, does it turn instantly into rock? (Bryan Rebhahn, Walden III Middle School, Racine, Wisconsin)

Yes, the outside solidifies instantly and the interior cools very quickly.

How would the eruption of an underwater volcano work if the water cools it so fast?

The lavas are erupted quickly and cool quickly. As more and more lavas makes it onto the sea-floor, the volcano will grow.

Hi, my name is Victor. I want to know which is the biggest volcano in the world and in which country the is it? Hey I like your job. Thank you. (Victor Avila, West View, California)

The biggest volcano in the world is in the United States - in Hawaii! The volcano is Mauna Loa on the big island of Hawaii and its big in terms of distance from its summit (4.619 meters about sea-level) to its base on the sea floo - a total distance of around 9 kilometers.

Hello my name is Mariel, and I would like to ask the scientist a question. What is so interesting about doing this video on volcanos? Please write back to me! Thank You! (Mariel Silva, West View Elementary, San Diego, California)

So we might inspire kids like you to become interested in science.

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Where is the closest volcano to San Diego, California? How long have you been studying volcanoes? What do you think was the best eruption of all time? (Michelle Valdez, West View, San Diego, California)

You don't have to travel far to get to see volcanic activity. Mammoth Mountain on the eastern side of the Sierra Nevada has lots of geothermal activity (associated with long valley caldera). About 5 - hours drive south in Baja, Mexico, are volcanic craters (San Quintin). I've been studying volcanoes since 1983 when I visited Iceland and climbed my first volcano - Hekla, the highest volcano in that beautiful country.
There are lots of interesting eruptions through time. I'm interested in Krakatoa in Indonesia. This volcano erupted in 1883, causing widespread damage. It was well documented and it interesting scientifically. I visited the volcano in 1992.
http://vulcan.wr.usgs.gov/Volcanoes/
Indonesia/Krakatau/framework.htm

How does the magma stay on top of the water to form an island? (Mike Mendiburu, West View Elementary, San Diego, California)

Lava builds up on top of previous lava flows until finally an island is born. The Hawaiian islands are a prime example.

Why were they sampling volcanoes if they were oceanographers? (Bryn Mawr, Maryland)

Volcanoes occur under water as well as on land. We study volcanoes where-ever they occur. Often we can learn about undersea volcanoes by looking at their on-land equivalents.

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Depending on the amount of molten lava released by the volcano, how long does it take to cool? (Kevin Singer, Racine, Wisconsin)

The lava cools by contact with the air and the earth. The upper and lower parts of a lava flow cool quickly but internally, the cooling rate will depend upon the thickness. Clearly, thicker flows should take longer to cool.

What was the biggest volcano ever recorded? (J.R.,Walden III Elementary School, Racine, Wisconsin)

Certainly one of the biggest volcanic eruptions in historical times (in terms of volume of material erupted) is Tambora in Indonesia, in 1815. The following year was known as the year without a summer due to the amount of ash put up into the atmosphere.
http://vulcan.wr.usgs.gov/Volcanoes/
Indonesia/Tambora/framework.html

What are the signs, a volcano gives, leading up to an eruption? (Christina Perez)

You might expect seismic activity as magma moves within a volcano plus changes in gravity. As each volcanic eruption is different, it is difficult to state definitively as to what changes are expected.

Does a volcano erupt quickly, or does it erupt gradually? (Jenni Lunde, Walden III Elementary School, Racine, Wisconsin)

Again, each eruption and each volcano are different. Some volcanoes blow their tops and release a huge amount of material very quickly (over hours or days) whereas others ooze out lava over months and years.

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My class has been studying volcanoes and my teacher said that the movie Volcano wasnt real. Why can't a volcano be in Los Angeles? (Calvin Brawn, Birmingham, England UK)

Hi Calvin,
Volcanoes occur in 3 types of environments - spreading ridges where the plates are pulled apart (like Iceland), subduction zones where plates come together with one going under the other (like Costa Rica) and at hotspots where deep-seated mantle plumes reach the surface (such as Hawaii). Los Angeles isn't one of these environments. Southern California is where the plates slide past one another (along the San Andreas Fault) so although there are plenty of earthquakes in Southern California (on the San Andreas Fault plus other faults) there isn't volcanic activity.

How do scientists measure the height of a volcano? (Archer, California)

Most volcanoes (I suspect) have been incorporated into the topographic surveys of their respective countries so their heights would be worked out by general surveying. Nowadays, GPS systems can record heights so it will be interesting to compare numbers.

Hi. I really like your website. It's really good! We've been learning about volcanoes in science class. How does a volcanic eruption effect the plants and animals on an island/landform? Does it give plants a better chance because of there being no humans or animals destroying the area? Thank you for your time! (MC)

Volcanoes (in the long term) are generally good for the surrounding areas - breakdown of the lavas gives rich soils so plants and animals can thrive. Short-term is a different story, and erupting volcanoes can destroy nearby habitats.

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How do volcanoes get lava? (Jose Whitter, New Mexico)

Melting produces magma which spills out of volcanoes to form lavas. See our animation.

How hot is lava? Can it burn you? What is lava made of? (Jason Carbone, Val Caron Public School, Ontario, Canada)

Lava is hot and it can burn you. It is made mainly of silicon and oxygen plus other elements such as aluminum, calcium, magnesium, sodium, and potassium.

What makes a volcano erupt? (Hannah Washington)

Usually a build-up of pressure - which could reflect the gas content of magma. An eruption acts to release the pressure by "blowing" material out to the atmosphere.

Does the amount of lava produced depend on the size of the volcano? (Jennifer)

Good question! Do large volcanoes give more lava? I don't think so. The volcanoes may be large because large amounts of lava erupted previously. But it doesn't necessarily follow tht future eruptions will also produce large amounts of lava. Mauna Loa, for example, is hugh yet it no longer produces large amounts of lava.

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