What's the Difference Between Magma and Lava?

[MULTIZ321]

What's the Difference Between Magma and Lava?
By Michael Greshko/ News/ National Geographic/ news.nationalgeographic.com

"And why do some volcanoes explode and others only ooze? It all comes down to their gooey centers.

Hawaii's Kilauea volcano keeps erupting with syrupy lava flows, serving as a fiery reminder of nature's destructive power. But as the ongoing eruption captures headlines, a question might occur to you: What's the difference between magma and lava?

The distinction between magma and lava is all about location. When geologists refer to magma, they're talking about molten rock that's still trapped underground. If this molten rock makes it to the surface and keeps flowing like a liquid, it's called lava.

Magmas vary in their chemical composition, which gives them—and the volcanoes that contain them—different properties.

Mafic magmas like those in Hawaii tend to form when the heavier crust that forms the ocean floor melts. They contain between 47 to 63 percent silica, the mineral that makes up glass and quartz. As far as molten rocks go, mafic magmas are fairly runny, with viscosities ranging from molasses to peanut butter. They're also the hottest variety of magma, reaching temperatures between 1,800 degrees to 2,200 degrees Fahrenheit...."

Lava from Hawaii's volcanoes tends to be comparatively runny due to its lower silica content.


Photograph by US Geological Survey

Be Sure to View the Slideshow of the "Stunning Photos of Volcanoes Around the World" that begins toward the end of the article.


Richard

 

[Carol C]

You are the Encyclopedia of TUG!

 

[Panina]

What's the Difference Between Magma and Lava?
By Michael Greshko/ News/ National Geographic/ news.nationalgeographic.com

"And why do some volcanoes explode and others only ooze? It all comes down to their gooey centers.

Hawaii's Kilauea volcano keeps erupting with syrupy lava flows, serving as a fiery reminder of nature's destructive power. But as the ongoing eruption captures headlines, a question might occur to you: What's the difference between magma and lava?

The distinction between magma and lava is all about location. When geologists refer to magma, they're talking about molten rock that's still trapped underground. If this molten rock makes it to the surface and keeps flowing like a liquid, it's called lava.

Magmas vary in their chemical composition, which gives them—and the volcanoes that contain them—different properties.

Mafic magmas like those in Hawaii tend to form when the heavier crust that forms the ocean floor melts. They contain between 47 to 63 percent silica, the mineral that makes up glass and quartz. As far as molten rocks go, mafic magmas are fairly runny, with viscosities ranging from molasses to peanut butter. They're also the hottest variety of magma, reaching temperatures between 1,800 degrees to 2,200 degrees Fahrenheit...."

Lava from Hawaii's volcanoes tends to be comparatively runny due to its lower silica content.


Photograph by US Geological Survey

Be Sure to View the Slideshow of the "Stunning Photos of Volcanoes Around the World" that begins toward the end of the article.


Richard

I just learned something new!

 

[DaveNV]

And then, for those heading to Hawaii, you need to know the difference between pahoehoe and a'a lava.

Dave

 

[MULTIZ321]

And then, for those heading to Hawaii, you need to know the difference between pahoehoe and a'a lava.

Dave

Ok Dave
Enlighten the uninformed.

Best Regards

Richard

 

[DaveNV]

Ok Dave
Enlighten the uninformed.

Best Regards

Richard

Pahoehoe lava has a comparatively smooth or "ropy" surface. The surface of an a'a flow consists of free chunks of very angular pieces of lava. This difference in form reflects flow dynamics. A'a forms when lava flows rapidly. The lava shown on TV currently erupting in Leilani Estates in Hawaii is a'a. The old joke is that it's the sound you make when walking across it barefoot.

The picture below shows pahoehoe flowing over older a'a lava:

There is a third type, called pillow lava, that forms underwater. But that's a different story.

Dave

 

[MULTIZ321]

Pahoehoe lava has a comparatively smooth or "ropy" surface. The surface of an a'a flow consists of free chunks of very angular pieces of lava. This difference in form reflects flow dynamics. A'a forms when lava flows rapidly. The lava shown on TV currently erupting in Leilani Estates in Hawaii is a'a. The old joke is that it's the sound you make when walking across it barefoot.

The picture below shows pahoehoe flowing over older a'a lava:

View attachment 6484

There is a third type, called pillow lava, that form underwater. But that's a different story.

Dave

Thanks for the elucidation

Richard