Explore topic-wise InterviewSolutions in .

Volcanologists are PROFESSIONALS who study VOLCANOES, whether dormant, active or extinct. They study these volcanoes to determine when volcanoes erupt, how it happens and why eruption OCCURS.

Volcanologists are professionals who study volcanoes, whether dormant, active or extinct. They study these volcanoes to determine when volcanoes erupt, how it happens and why eruption occurs.

The word "volcano" comes from the Roman God of Fire. Also the small volcanic island of Vulcano in the Aeolian Islands off SICILY, was called after that god. Apparently, this island was highly active in Ancient times and people believed its crater was the chimney of the Vulcanus' forge, where the hot lava and ash coming out from the crater were the VISIBLE evidence of his activity to forge weapons for the other gods. 

On Hawai'i, the people attributed volcanic activity to the beautiful, but capricious and at times destructive goddess PELE, who loved fire and hated WATER.

The word "volcano" comes from the Roman God of Fire. Also the small volcanic island of Vulcano in the Aeolian Islands off Sicily, was called after that god. Apparently, this island was highly active in Ancient times and people believed its crater was the chimney of the Vulcanus' forge, where the hot lava and ash coming out from the crater were the visible evidence of his activity to forge weapons for the other gods. 

On Hawai'i, the people attributed volcanic activity to the beautiful, but capricious and at times destructive goddess Pele, who loved fire and hated water.

• An active volcano is a volcano that has had at least one eruption during the PAST 10,000 years. An active volcano might be ERUPTING or dormant.
• An erupting volcano is an active volcano that is having an eruption.
• A dormant volcano is an active volcano that is not erupting, but supposed to ERUPT again.
• An extinct volcano has not had an eruption for at least 10,000 years and is not expected to erupt again in a comparable time SCALE of the FUTURE.

Volcanoes are usually less DANGEROUS than other natural hazards such as earthquakes, tsunamis and hurricanes.

Volcanoes have a serious of hazards (e.g. lava FLOWS, ash fall, pyroclastic flows, climate changes on a global scale) that relate into DIFFERENT dangers or risks. The risks when visiting an active volcano depend on which RISK ZONES of the volcano are visited and for how long.

Volcanoes are usually less dangerous than other natural hazards such as earthquakes, tsunamis and hurricanes.

Volcanoes have a serious of hazards (e.g. lava flows, ash fall, pyroclastic flows, climate changes on a global scale) that relate into different dangers or risks. The risks when visiting an active volcano depend on which risk zones of the volcano are visited and for how long.

CLASSIFICATION of the world's most dangerous VOLCANOES is subject to debate. Below are listed some of the most dangerous volcanoes DUE to their explosive HISTORY and proximity to LARGE population centres.

Classification of the world's most dangerous volcanoes is subject to debate. Below are listed some of the most dangerous volcanoes due to their explosive history and proximity to large population centres.

• The classic SYMMETRICAL volcano CONE shape is one of the most impressive sights in nature. Of the world's 1500 active volcanoes a few stand out as being exceptionally beautiful.
• Mt FUJI is Japan is renowned for its beauty. There are several other volcanoes which have an even more beautiful shape.
• Kronotsky volcano in Kamchatka is even more beautiful than Fuji, and MAYON volcano in Philippines is one of the most spectacular in its shape.

• Large volcanic eruptions can cause global climate change and EVEN be responsible for mass extinctions.
• MAJOR eruptions in Kamchatka Peninsula, Russia have a disproportionate effect on global climate, due to the LOW troposphere elevation at these latitudes, and the ease of dispersal of ash, AEROSOL, and gas.
• Most mass extinctions during the last 500 million years coincide with eruptions of large igneous provinces. The Cretaceous-Tertiary extinction was synchronous with the Deccan flood volcanism.
• There is a positive feedback between glacial variability and atmospheric CO2 concentrations: glaciation increases volcanic eruptions, raises atmospheric
• CO2, and causes more glaciation. Conversely, waning volcanic activity during an interglacial could lead to a reduction in CO2 and the onset of an ice age.

The size of volcanic eruptions is determined by the amount of lava emitted. The largest eruption over the past 2 centuries was Tambora in INDONESIA in 1815.

• Laki fissure, Iceland 1783
• Tambora, Indonesia 1815
• Cosiguina, Nicaragua 1835
• Askja, Iceland 1875
• Krakatau, Indonesia 1883
• Tarawera, NEW ZEALAND 1886
• Santa Maria, Guatemala 1902
• Ksudach, Kamchatka 1907
• Katmai, Alaska, USA 1912
• Agung, Indonesia 1963
• St. Helens, USA 1980
• El Chichón, Mexico 1982
• Pinatubo, Philippines 1991
• Chaiten, Chile 2008

The size of volcanic eruptions is determined by the amount of lava emitted. The largest eruption over the past 2 centuries was Tambora in Indonesia in 1815.

• The volcanic explosivity index is a scale from 1 to 8 to measure the magnitude (ERUPTED volume) and intensity 
• (eruption COLUMN height) of an eruption. 
• The VEI is not USED to DESCRIBE eruptions of lava which are non explosive. 
• Ancient eruptions are determined by the volume of deposits. 
• Modern eruptions are determined by the observed column height.

KILAUEA volcano on Hawaii is the WORLD's most ACTIVE volcano, followed by Etna in Italy and PITON de la Fournaise on La Réunion island. 

After that, it is difficult to decide the exact order on the list, but the following are very close: Stromboli, Merapi, Erta ALE, Ol Doinyo Lengai, Unzen, Yasur, Ambrym, Arenal, Pacaya, Klyuchevsky, Shiveluch, and Erebus.

Kilauea volcano on Hawaii is the world's most active volcano, followed by Etna in Italy and Piton de la Fournaise on La Réunion island. 

After that, it is difficult to decide the exact order on the list, but the following are very close: Stromboli, Merapi, Erta Ale, Ol Doinyo Lengai, Unzen, Yasur, Ambrym, Arenal, Pacaya, Klyuchevsky, Shiveluch, and Erebus.

volcanoes are RESPONSIBLE for FORMING the atmosphere which is PRETTY IMPORTANT.

volcanoes are responsible for forming the atmosphere which is pretty important.

Long Valley Caldera is in central EASTERN California, essentially at the town of MAMMOTH LAKES.

Long Valley Caldera is in central eastern California, essentially at the town of Mammoth Lakes.

• We sometimes are being asked if the number of currently active volcanoes and ongoing eruptions, or global volcanic ACTIVITY, has been increasing recently. Should we be worried "globally"
• The current LEVEL of volcanic activity is completely normal, on the contrary (if not on the low end of averages over decades).
• The main difference is that there is faster and more information available, as well as increased MEDIA coverage and public INTEREST on the subject of global volcanic activity. This MIGHT give the impression that volcanic activity is on the increase (which it is not).

It is much more difficult to predict the END of an eruption than to predict its BEGINNING. The table below gives the length of time that volcanoes erupt. 

Explosive ERUPTIONS end when sufficient decompression is ATTAINED to cause magma chamber collapse and RESTORATION of the initial pressure conditions.

It is much more difficult to predict the end of an eruption than to predict its beginning. The table below gives the length of time that volcanoes erupt. 

Explosive eruptions end when sufficient decompression is attained to cause magma chamber collapse and restoration of the initial pressure conditions.

Volcanic eruptions are not the most dangerous of NATURAL DISASTERS. They cause less fatalities than earthquakes, hurricanes and famines.

In the PAST 200 years, there have been over 200,000 deaths in volcanic eruptions. Four causes resulted in 91% of the fatalities - 

famine and epidemic disease (30%), PYROCLASTIC flows (27%), lahars (17%), and TSUNAMIS (17%).

Volcanic eruptions are not the most dangerous of natural disasters. They cause less fatalities than earthquakes, hurricanes and famines.

In the past 200 years, there have been over 200,000 deaths in volcanic eruptions. Four causes resulted in 91% of the fatalities - 

famine and epidemic disease (30%), pyroclastic flows (27%), lahars (17%), and tsunamis (17%).

Misti is just over 19,000 FEET high which is easily the highest volcano that I have ever studied. However, because it is an ISLAND and a large PART of the volcano is below sea-level Erebus is the OVERALL LARGEST volcano that I have ever studied.

Misti is just over 19,000 feet high which is easily the highest volcano that I have ever studied. However, because it is an island and a large part of the volcano is below sea-level Erebus is the overall largest volcano that I have ever studied.

VOLCANISM is a MAJOR factor on all of the terrestrial planets, so it has had a HUGE affect in forming the EARTH, MARS, and Venus.

Volcanism is a major factor on all of the terrestrial planets, so it has had a huge affect in forming the Earth, Mars, and Venus.

Some volcanic eruptions THROUGHOUT history have been significant in their CONTRIBUTION to science. The following VOLCANOES were significant for their contribution to KNOWLEDGE about eruptions, or occurred close to large populations.

Some volcanic eruptions throughout history have been significant in their contribution to science. The following volcanoes were significant for their contribution to knowledge about eruptions, or occurred close to large populations.

When there are no SIGNS of an active magma chamber BENEATH the volcano (no unusual seismic ACTIVITY, no volcanic gasses ESCAPING etc.), and when there hasn't been any activity for a long time span (at least 10,000 years).

When there are no signs of an active magma chamber beneath the volcano (no unusual seismic activity, no volcanic gasses escaping etc.), and when there hasn't been any activity for a long time span (at least 10,000 years).

MANY volcanoes have been in continuous eruption for DECADES. Etna, Stromboli, and Yasur have been erupting for hundreds or thousands of YEARS.

The following 4 volcanoes EMIT the most lava. KILAUEA (Hawaii), Mt Etna (Italy), Piton de la Fournaise (Réunion), Nyamuragira, (D.R. Congo)

Many volcanoes have been in continuous eruption for decades. Etna, Stromboli, and Yasur have been erupting for hundreds or thousands of years.

The following 4 volcanoes emit the most lava. Kilauea (Hawaii), Mt Etna (Italy), Piton de la Fournaise (Réunion), Nyamuragira, (D.R. Congo)

• The size of VOLCANIC eruptions is determined by the amount of lava emitted. The largest eruption over the PAST 2 CENTURIES was Tambora in Indonesia in 1815.
• Large volcanic eruptions are more frequent than asteroid impacts of similar MAGNITUDE.