Showing posts with label volcanos. Show all posts
Showing posts with label volcanos. Show all posts

March 1 - Happy Birthday, Yellowstone National Park!

Posted on March 1, 2021

This is an update of my post published on March 1, 2010:



 
Yellowstone National Park was the first national park in the world. Established on this date in 1872, it features a beautiful lake, forests, a “Grand” canyon, waterfalls, exciting wildlife such as bison and bears, elk and moose...





...But Yellowstone is most famous for having lots and lots of fascinating thermal activity. There are rainbow-colored hot springs, steaming rivers and lakes, mud volcanoes, several thousand steam vents, and from 300 to 500 geysers— more than half of all the geysers in the world! 




Yellowstone has a LOT of geysers.

Yellowstone is mostly in the state of Wyoming, but parts spill over into Idaho and Montana. It is well worth even a long trek to see it! 



Yellowstone Caldera is the largest "supervolcano" in North America and one of the largest in the world. (A caldera is a large crater formed by a volcanic explosion or by the collapse of a volcanic cone.)

Most people think of a volcano as a mountain that sometimes blows its top; Mount Saint Helens in Washington with its 2-square-mile crater is a good example of that “typical” volcano. 

Mount Saint Helens, before and after blowing her top in 1980.


Yellowstone Caldera, which hasn't had a major eruption for hundreds of thousands of years, is a giant depression, not a mountain—but it, too, can be defined as a volcano! All 1,500 square miles of it! 

According to the U.S. National Park Service, fully half of the world's geothermal features (such as hot springs, mud pots, and geysers) are in Yellowstone. With 10,000 different features, no website can possibly show them all, but Terra Galleria has a lot of beautiful images. (After enjoying the thumbnails, and perhaps clicking your favorites to see a larger version, you might want to check out the “large format photos” and “panoramic photos” pages!) 




There are several "virtual tours" of Yellowstone on the internet. This website has links to GoogleEarth's flyover of Norris Basin plus and to various webcams. 

The National Park's website has a photo gallery, videos, and some virtual tours.

Watch geysers erupt on Yellowstone's webcams. 

Make a “geyser” at home! This YouTube video has an activity with soda and Mentos. Be sure to point out to your kids that what is going on in this activity is in no way related to actual geysers, which are created by hot water under pressure! (Also, notice that diet soda works better than sugary soda and is FAR less messy/sticky than “regular”!) 

Watch an animation that explains how geysers erupt. 

More than just geysers! Other features at Yellowstone include (as mentioned above) hot springs and mudpots. And there are terraces. And fumaroles. And and and...!

A fumarole is a hole from which steam and other (sometimes stinky) gases escape. Here are experiments to find out more about hot springs and fumaroles. BE SURE to read the entire instructions and follow those instructions carefully WITH AN ADULT! (Scroll down around halfway down the page to see the instructions.)




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January 23 – Mauna Loa Begins 300-Day Eruption

Posted on January 23, 2017

I think of volcanoes erupting over a matter of minutes or hours – not for the better part of a year!

But that's because I think of volcanic eruptions as violent explosive outbursts of lava and gas and steam. Mauna Loa, in Hawaii, is the largest volcano on the planet partly because its lava tends to be silica poor, and therefore the lava eruptions tend to be very fluid, non-explosive, gentler and slower-moving than many other volcano's eruptions, although often still quite destructive.

So...why does having silica-poor lava relate to being a large volcano? Simply stated, Mauna Loa doesn't blow off its top!

These pictures of another volcano, Mt. St. Helens,
shows that some volcanos DO blow their tops off!
Check out the lovely cone that is Mauna Loa, below:

The slopes of Mauna Loa are generally gentle. The cooling lava makes the volcano larger – and, incidentally, makes the island of Hawaii larger. The volume of the volcano is estimated to be about 18 thousand cubic miles (75 thousand cubic kilometers).

By the way, even though Mauna Loa is the largest volcano on Earth, we are talking about that huge volume, not its height. It isn't the highest volcano on Earth, and even its island neighbor, Mauna Kea, is higher by about 120 feet (37 meters).

Now, about that 300-day eruption!

On this date in 1859, Mauna Loa had a brief summit eruption. Then a stream of lava broke out from the volcano's flank (side), high up but not at the top. This outbreak of lava created a 32-mile-long lava flow, the longest in the state of Hawaii.

On the evening of January 30 the lava began to destroy the village of Wainanali'i on the west coast of the island. I gather that no lives were lost, but some people lost everything they owned as well as their homes. However, since Mauna Loa's lava moves relatively slowly, many people were able to gather their most precious belongings and personal effects before escaping to higher ground.

By January 31 the lava reached the ocean. This was eight days after the eruption started – and, amazingly, the eruption continued another 292 days! As the lava continued to flow, it filled fishponds and of course impacted the economy of several communities.

The science of volcanology was extended during this eruption, since a'a and pahoehoe lava flows could be studied and compared. It turns out that the two kinds of lava are identical chemically; the difference is in their temperature. A'a lava flows become cool enough that they cannot flow, and so a more broken-up, rougher rock forms, compared to the smooth-flowing pahoehoe lava flows.

A'a lava forming, above,
and cool a'a lava, below.


Pahoehoe lava forming, above,
and cool pahoehoe lava, below. 



Also on this date:


Anniversary of a Record-Setting Dive 





















































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