Natural Hazards

Can lakes near volcanoes become acidic enough to be dangerous to people and animals?

Yes. Crater lakes atop volcanoes are typically the most acid, with pH values as low as 0.1 (very strong acid). Normal lake waters, in contrast, have relatively neutral pH values near 7.0.

The crater lake at El Chichon volcano in Mexico had a pH of 0.5 in 1983 and Mount Pinatubo's crater lake had a pH of 1.9 in 1992. The acid waters of these lakes are capable of causing burns to human skin but are unlikely to dissolve metal quickly. Gases from magma that dissolve in lake water to form such acidic brews include carbon dioxide, sulfur dioxide, hydrogen sulfide, hydrogen chloride, and hydrogen fluoride.

Acidic lakes that are capable of dissolving an aluminum boat in a matter of minutes (as seen in movies) are not realistic.

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Image: Damage from 2011 Virginia Earthquake

Do earthquakes large enough to collapse buildings and roads accompany volcanic eruptions?

Not usually. Earthquakes associated with eruptions rarely exceed magnitude 5, and these moderate earthquakes are not big enough to destroy buildings and roads. The largest earthquakes at Mount St. Helens in 1980 were magnitude 5, large enough to sway trees and damage buildings, but not destroy them. During the huge eruption of Mount Pinatubo in...

Volcano erupting and spewing a huge cloud of rock and ash into the sky.

Can volcanic eruptions endanger helicopters and other aircraft?

Yes. Encounters between aircraft and clouds of volcanic ash are a serious concern. Jet engines and other aircraft components are vulnerable to damage by fine, abrasive volcanic ash, which can drift in dangerous concentrations hundreds of miles downwind from an erupting volcano. In the past, many aircraft have accidentally encountered volcanic ash...

Image: Valley of Ten Thousand Smokes, Alaska

What was the largest volcanic eruption in the 20th century?

The World's largest eruption of the 20th century occurred in 1912 at Novarupta on the Alaska Peninsula. An estimated 15 cubic kilometers of magma was explosively erupted during 60 hours beginning on June 6th. This volume is equivalent to 230 years of eruption at Kilauea (Hawaii) or about 30 times the volume erupted by Mount St. Helens (Washington...

Appalachian Plateau Groundwater Availablity Study-newriver2

Will extinct volcanoes on the East Coast of the U.S. erupt again?

No. Through plate tectonics, the eastern U.S. has been isolated from the global tectonic features (tectonic plate boundaries and hot spots in the mantle), that cause volcanic activity. So new volcanic activity is not possible now or in the near future. If you wait around several hundred million years, maybe... Remnants of past volcanism are found...

Image: Aerial View of Mauna Loa Volcano, Hawaii

Where is the largest active volcano in the world?

Rising gradually to more than 4 km above sea level, Hawaii’s Mauna Loa is the largest volcano on our planet. Its submarine flanks descend to the sea floor an additional 5 km (3 mi), and the sea floor in turn is depressed by Mauna Loa's great mass another 8 km (5 mi). This makes the volcano's summit about 17 km (10.5 mi) above its base!

High-resolution lidar image of Mount St. Helens, Washington.

What was the most destructive volcanic eruption in the history of the United States?

The May 18, 1980 eruption of Mount St. Helens (Washington) was the most destructive in the history of the United States. Novarupta (Katmai) Volcano in Alaska erupted considerably more material in 1912, but owing to the isolation and sparse population of the region, there were no human deaths and little property damage. In contrast, the eruption of...

Lava splashes from a lava lake.

What is the difference between "magma" and "lava"?

Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth's surface.

Samples to OGRL thumbnail

What are some benefits of volcanic eruptions?

Over geologic time, volcanic eruptions and related processes have directly and indirectly benefited mankind. Volcanic materials ultimately break down and weather to form some of the most fertile soils on Earth, cultivation of which has produced abundant food and fostered civilizations. The internal heat associated with young volcanic systems has...

Image: Valley of Ten Thousand Smokes, Alaska

Can an eruption at one volcano trigger an eruption at another nearby volcano?

There are a few historic examples of simultaneous eruptions from volcanoes or vents located within about 10 km of each other, but it's very difficult to determine whether one eruption caused the other. To the extent that these erupting volcanoes or vents have common or overlapping magma reservoirs and hydrothermal systems, magma rising to erupt...

Ash and plume lightning over the Sakurajima volcano, southern Japan eruption in February of 2013

Do volcanoes affect weather?

Yes, volcanoes can affect weather and the Earth's climate . Following the 1991 eruption of Mount Pinatubo in the Philippines, cooler than normal temperatures were recorded worldwide and brilliant sunsets and sunrises were attributed to this eruption that sent fine ash and gases high into the stratosphere, forming a large volcanic cloud that...

Screenshot of Volcanoes and Current Activity Alerts

How many active volcanoes are there on Earth?

There are about 1,500 potentially active volcanoes worldwide, aside from the continuous belts of volcanoes on the ocean floor at spreading centers like the Mid-Atlantic Ridge . About 500 of those 1,500 volcanoes have erupted in historical time. Many of those are located along the Pacific Rim in what is known as the " Ring of Fire ." In the United...

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Year Published: 2019

Living with volcano hazards

Volcanic eruptions are among Earth’s most dramatic and powerful agents of change. Ash, mudflows, and lava flows can devastate communities near volcanoes and cause havoc in areas far downwind, downstream, and downslope. Even when a volcano is quiet, steep volcanic slopes can collapse to become landslides, and large rocks can be hurled by powerful...

Stovall, Wendy K.; Driedger, Carolyn L.; Westby, Elizabeth G.; Faust, Lisa M.

Attribution: , Volcano Hazards

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Stovall, W.K., Driedger, C.L., Westby, E.G., and Faust, L.M., 2019, Living with volcano hazards: U.S. Geological Survey Fact Sheet 2018–3075, 6 p., https://doi.org/10.3133/fs20183075.

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Year Published: 2018

2018 update to the U.S. Geological Survey national volcanic threat assessment

When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U....

Ewert, John W.; Diefenbach, Angela K.; Ramsey, David W.

Attribution: , Volcano Hazards

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Ewert, J.W., Diefenbach, A.K., and Ramsey, D.W., 2018, 2018 update to the U.S. Geological Survey national volcanic threat assessment: U.S. Geological Survey Scientific Investigations Report 2018–5140, 40 p., https://doi.org/10.3133/ sir20185140.

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Year Published: 2000

Mount Mageik: A compound stratovolcano in Katmai National Park: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

Mount Mageik is an ice-clad 2,165-m andesite-dacite stratovolcano in the Katmai volcanic cluster at the head of the Valley of Ten Thousand Smokes. New K-Ar ages indicate that the volcano is as old as 93±8 ka. It has a present-day volume of 20 km3 but an eruptive volume of about 30 km3, implying a longterm average volumetric eruption rate of about...

Hildreth, Wes; Fierstein, Judy; Lanphere, Marvin A.; Siems, David F.

Attribution: , Volcano Hazards

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Fumarole on Kīlauea Volcano, Hawaiʻi. Elemental sulfur vapor escaping from the fumarole has cooled to form yellow-colored crysta

April 14, 2016

Fumarole on Kīlauea Volcano, Hawaiʻi

Fumarole on Kīlauea Volcano, Hawaiʻi. Elemental sulfur vapor escaping from the fumarole has cooled to form yellow-colored crystals around its margins. Credit: Robert L. Christiansen.

http://volcanoes.usgs.gov/vsc/glossary/fumarole.html

Attribution: Volcano Hazards, Hawaiian Volcano Observatory, Kīlauea

Hot springs in Yellowstone.

April 11, 2016

Hot springs in Yellowstone.

Attribution: Northern Rocky Mountain Science Center (NOROCK)

Image: Sampling Acid Mine Drainage in Elk_County, PA

November 6, 2007

Sampling Acid Mine Drainage in Elk_County, PA

Sampling acid mine drainage residuals in Elk County, Pennsylvania. The USGS has pioneered a new use for these residuals that are currently a disposal challenge, using them to filter phosphorus from agricultural and municipal wastewaters.

Image: Lake Tyrrel. Acid Lake

September 20, 2007

Lake Tyrrel. Acid Lake

Jim Crowley (USGS), Jeff Kargel (University of Arizona. Studying Earth as a Mars analog.

Image: Lake Chandler. Acid Lake

September 18, 2007

Lake Chandler. Acid Lake

Jim Crowley (USGS) measuring pH in the acid lake Chandler in Australia.

Image: Green Lake. Acid Lake

September 17, 2007

Green Lake. Acid Lake

Jim Crowley (USGS), Nathan Bridges (JPL). Field trip to Australia to study acid lakes as Mars analogs.

Image: Davis Rd. Carbon Dioxide Vent

December 25, 2004

Davis Rd. Carbon Dioxide Vent

Davis Rd. carbon dioxide vent, Salton Sea, California.

Image: Measuring a Superheated Fumarole

September 30, 1998

Measuring a Superheated Fumarole

USGS geochemist Bill Evans measures the temperature of a superheated (hotter than the boiling point) fumarole in Lassen Volcanic National Park.

Large umbrella shaped cloud of volcanic ash viewed from a distance

June 15, 1991

Giant ash cloud from the eruption of Mount Pinatubo, 1991

Giant ash cloud from the eruption of Mount Pinatubo, 1991 towering above farms and agricultural lands in the Philippines.

Attribution: Natural Hazards, Volcano Hazards, Alaska

Image: Sampling a Fumarole

July 31, 1990

Sampling a Fumarole

USGS geochemist Cathy Janik (left) and Iceland Geosurvey chemist Jón Örn Bjarnason (right) collect a gas sample from a fumarole in Lassen Volcanic National Park.

Image: CO2 Hazard Area sign

CO2 Hazard Area sign

CO2 Hazard sign at Horseshoe Lake.

Attribution:

Image: Natural Iron-rich Acidic Spring Flowing into Cement Creek

Natural Iron-rich Acidic Spring Flowing into Cement Creek

Photograph showing natural iron-rich acidic spring flowing into Cement Creek near Silverton, Colorado. Similar natural springs contribute water to Cement Creek and other tributaries of the upper Animas River.