The following questions were answered by expert volcanologist Dr. Stanley Williams.

Why did you want to study volcanoes?
I decided to study volcanoes when I learned how the 1902 eruption of Mount Pelee, which killed 28,000 people, had also taught very important lessons to scientists. Then I heard about how volcanologists can actually watch the volcanic eruptions with their own eyes and study them using special instruments. Being a volcanologist is unique because you can directly observe the active processes that make the earth. However, most geologists study what happened a few million years ago.

How many volcanoes have you studied?
I have been on about 125 volcanoes in 20 countries.

Out of all the volcanoes you have explored, which one was the most exciting?
It is really hard to decide which ones were the most exciting because they are all exciting. Once, I remember I was in the Canary Islands with my professor and we agreed that we had seen more things for the first time there than we could remember having seen before. They were beautiful islands with very different kinds of volcanoes. In Papua New Guinea, my student and I were really close to the volcano, Tavurvur while it was erupting. It was pretty intense with the roaring, slamming, ground-shaking eruption happening about 1.5 kilometers from us and ash raining down all over us. It was both exciting and terrifying at the same time.

What volcano do you like studying the most?
That is not easy to say because I am a lucky person who really enjoys his work. My favorite is probably Masaya, which is in Nicaragua. It is a very active volcano and has had many violent eruptions. The capital of Nicaragua, Managua, is close to Masaya. It is very important to study Masaya in order to protect the residents of Managua from future eruptions.

Have you ever studied Mount St. Helens?
I was amongst the very first scientists to go Mount St. Helens two months before the big eruption. We heard about the first signs of eruptions around noon on March 20, and we left at 4:00 that afternoon with 14 suitcases full of instruments and gear. It was extremely exciting to see an erupting volcano in the U.S.

What does it look like inside a volcano?
Inside a volcano crater, there are lots rocks and some of them are covered with beautifully colored minerals. Rocks covered by sulfur are bright yellow and the others, because of different chemical combinations, cover the spectrum of color. There are small holes releasing gases, which we call fumaroles, that we search for because they are sort of like "windows" into the earth. We can learn a lot about what is really going on at great depth.

How far down can you go into a volcano?
The crater of most volcanoes is about as deep as a football field is long (approximately 100 yards). It is a deep basin into which you climb. The crater may be as wide as 500 meters, or about one fourth of a mile.

What does it feel like when you are inside a volcano?
When you are inside the crater of an active volcano it is sort of like being inside the mouth of a lion — you just hope that the lion does not decide to swallow! It is scary and you must try to work quickly and not stay too long. My professor and I actually slept in a crater of Momotombo in Nicaragua, but it was a bad idea. The ground was so hot that we felt like chickens on a rotisserie being cooked!

What is an erupting volcano like?
When a volcano erupts, it is usually incredibly loud. There are sounds of explosions, rocks breaking, and gases rushing out of the crater. Within a few minutes, a column of ash and gas may build to great height. At Mount St. Helens, the column went to 28 kilometers in a few minutes.

Do you need to wear protective gear so that you don't get too hot?
There is not really much to wear that can protect you from the heat because it is so strong. It is important to be very careful and to move slowly so that you can see the very hot gases. If you walk into the gases, they would kill you. I do wear a gas mask so that the gases do not kill me, a helmet so that the rocks do not break my skull again, and some very heavy gloves so that I can pick up hot rocks.

What are the living conditions like on your work sites?
When I'm on location, I often live in the backwoods and eat what is available and is the local custom. For example, in Mexico, I once ate a plate full of cooked worms and another of ant eggs. In Japan, I have eaten just about everything that I can get down my throat — and most of it was RAW. In Colombia, near Galeras, I ate guinea pigs! They are really pretty good. Sometimes I camp out in tents, sometimes but usually I stay in a small inn or hotel. To get around the sites, I often ride horses or mules or I drive. And, of course, I do a lot of walking.

What type of equipment do you use to locate and identify minerals in a volcano?
We take the minerals that we collect to the university laboratory where we use X-rays to see what they are. We have identified many new minerals. One of them is called stoiberite, the name of my professor. He was honored by having a mineral named after him.

Please complete the sentence: "The one thing I would most like to know about volcanoes is...
I would like to know if the dinosaurs really died out because of a huge volcanic eruption or because a meteorite crashed into the earth.