California Super Volcano Grumbles But Little Chance Of Eruption

From the Daily Mail: "Is California's supervolcano set to blow? Scientists identify more than 2,000 quakes at the Long Valley Caldera that they say 'are precursors for an eruption'." 

    Scientists at the California Institute of Technology (Caltech) identified over 2,000 earthquakes rumbling throughout the Long Valley Caldera in recent years.

    The team conducted a new investigation to see if the seismic activity was a sign of impending doom or that the risk of a massive eruption was decreasing.

    Caltech researchers created detailed underground images of the caldera, finding that the recent seismic activity results from fluids and gases released as the area cools off and settles down.

    The study author Zhongwen Zhan said: 'We don't think the region is gearing up for another supervolcanic eruption, but the cooling process may release enough gas and liquid to cause earthquakes and small eruptions.

    'For example, in May 1980, there were four magnitude 6 earthquakes in the region alone.'

The article also adds that "[t]he long-dormant volcano was the site of a super explosion 767,000 years ago, releasing 140 miles of volcanic material into the atmosphere and devastating the land." 

    While it may seem that volcanic eruptions or volcanic activity is increasing, that is an illusion. Rather, we are increasingly more aware of volcanic activity. See:

• "Volcanic Activity Isn't Increasing Across the Planet"--Discover Magazine.
• "Has volcanic activity been increasing?"--Smithsonian Institute.

In fact, using the Volcanic Explosivity Index (VEI), we haven't had a volcanic explosion above VEI 6 since the Mount Tambora eruption of 1815. (See, "The 12 biggest volcanic eruptions in recorded history"--Live Science). It is also notable that atmospheric loading of aerosols and dust due to volcanic activity has actually been quite low over the past century compared to prior periods, according to the graph below:

(Source: "Ice-Core-Based Volcanic Atmospheric Injection and Loading for the Past 1500 Years"--Rutgers University).

    And the impact on climate can be significant as I've written about many times before. For instance, this article from the Smithsonian Magazine--"Sixth-Century Misery Tied to Not One, But Two, Volcanic Eruptions"--relates the following:

    The researchers detected 238 eruptions from the past 2,500 years, they report today in Nature. About half were in the mid- to high-latitudes in the northern hemisphere, while 81 were in the tropics. (Because of the rotation of the Earth, material from tropical volcanoes ends up in both Greenland and Antarctica, while material from northern volcanoes tends to stay in the north.) The exact sources of most of the eruptions are as yet unknown, but the team was able to match their effects on climate to the tree ring records.

    The analysis not only reinforces evidence that volcanoes can have long-lasting global effects, but it also fleshes out historical accounts, including what happened in the sixth-century Roman Empire. The first eruption, in late 535 or early 536, injected large amounts of sulfate and ash into the atmosphere. According to historical accounts, the atmosphere had dimmed by March 536, and it stayed that way for another 18 months.

    Tree rings, and people of the time, recorded cold temperatures in North America, Asia and Europe, where summer temperatures dropped by 2.9 to 4.5 degrees Fahrenheit below the average of the previous 30 years. Then, in 539 or 540, another volcano erupted. It spewed 10 percent more aerosols into the atmosphere than the huge eruption of Tambora in Indonesia in 1815, which caused the infamous “year without a summer”. More misery ensued, including the famines and pandemics. The same eruptions may have even contributed to a decline in the Maya empire, the authors say.

    “We were amazed at the close correspondence and the consistency of the climate response to volcanic sulfate forcing during the entire 2,500-year period,” says coauthor Joe McConnell of the Desert Research Institute. “This clearly shows the marked impact that volcanic eruptions have on our climate and, in some cases, on human health, economics and so history.”

Related Posts:

• "The Mysterious Eruption of 1258 A.D."
• "The 1783 Laki Volcanic Eruption in Iceland"
• "10 Most Powerful Volcanic Explosions in Past 2000 Years"
• "Volcanoes and the Beginning of the Little Ice Age"
• "Documentary on the Mt.Tambora Eruption"
• "How Big Was the Tambora Explosion?"
• "The 1815 Mt. Tambora Explosion"
• "Documentary On The Krakatoa Explosion of 535 A.D."