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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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.
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.
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.
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.
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.
Lake Tyrrel. Acid Lake
Jim Crowley (USGS), Jeff Kargel (University of Arizona. Studying Earth as a Mars analog.
Lake Chandler. Acid Lake
Jim Crowley (USGS) measuring pH in the acid lake Chandler in Australia.
Green Lake. Acid Lake
Jim Crowley (USGS), Nathan Bridges (JPL). Field trip to Australia to study acid lakes as Mars analogs.
Davis Rd. Carbon Dioxide Vent
Davis Rd. carbon dioxide vent, Salton Sea, California.
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.
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.
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.
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.