Geology, Homeschooling, Local Travel

Virtual Geology Tour Series – Volcanoes

Did you miss my Geology Tours? No worries. Watch these videos of volcanoes with me and learn a few things about volcanoes.

Iceland Volcanic Eruption

Iceland is a land of ice and fire, due to its location near the Arctic Circle and its position on top of a mid-ocean ridge and a hot spot. It has many glaciers, including a large ice sheet that covers 25% of the country. Beneath the ice are a half dozen basaltic volcanoes, similar to the snow- and ice-covered one. In 1996, a volcanic eruption beneath an ice sheet melted the ice, releasing a catastrophic flood of meltwater. The huge flood carried blocks of ice, rock, and other debris, causing widespread destruction and covering vast area with sediment.

Exploring Geology 2nd Edition, Reynolds, S. J. et.al., page 149

All volcanoes in Iceland are products of hotspot related to mid-ocean ridge – the type of magma produced by these are basaltic. Basaltic lavas are thin or less viscous, similar to Hawaiian lavas thus, flow like water down the volcano’s slopes. In contrast, the lavas of Mayon volcano, for example, is andesitic and more viscous thus, flow down the slopes more slowly. Watch how basaltic lava flows down the slopes of this volcano in Iceland from the YouTube channel, Green Iceland Vid. The video was taken just last July 17, 2021. The author did not mention the name of the volcano in the description box but I guessed it’s the same one in the next video, Geldingadalir volcano, basing on timeline.

The video below is a 17-day time-lapse video of Geldingadalir volcano on the Reykjanes peninsula in Iceland, from March 20, 2021 at GMT12:00 to the first 6 hours from when the new fissures opened up April 3, 2021 GMT18:00. The channel has more videos of this volcano while it is erupting so feel free to check it out.

Look down into the crater of the same volcano above as it erupts, 6 years ago. Sad that a few drones had to be sacrificed to take stunning these shots. Kudos to National Geographic’s team for their work!

Philippine Volcanoes

In the article I wrote last year about Taal’s phreatic eruption, I tried to explain in layman how such an eruption happens. I looked for videos of Philippine volcanoes as they are erupting and here are just some of the legit ones I found. Enjoy watching!

In this video by BBC, a short clip of the phreatic eruption as taken by PHIVOLCS-installed camera inside the crater, plus, volcanic cloud with lightning, and the devastation on the island afterwards are shown.

Video below shows snippets of how local TV news covered the eruption of Mt. Pinatubo in 1991 which was to this day, one of the biggest eruptions to ever occur around the world in historic time. The erupted ash covered the whole country and reached neighboring Asian countries as well. The said eruption caused a global drop in temperature of about 1 degrees C, if I remember correctly.

The largest volcanic eruption in recent history, the blast of Mount Pinatubo in the Philippines, affected climate around the world, causing temperatures to drop and Asian rain patterns to shift temporarily. 

https://www.livescience.com/14513-pinatubo-volcano-future-climate-change-eruption.html

When Mount Pinatubo erupted in the Philippines June 15, 1991, an estimated 20 million tons of sulfur dioxide and ash particles blasted more than 12 miles (20 km) high into the atmosphere. The eruption caused widespread destruction and loss of human life. Gases and solids injected into the stratosphere circled the globe for three weeks. Volcanic eruptions of this magnitude can impact global climate, reducing the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the troposphere, and changing atmospheric circulation patterns. The extent to which this occurs is an ongoing debate.

https://earthobservatory.nasa.gov/features/Volcano

The biggest devastation in areas surrounding Mt. Pinatubo was caused by the lahar flows that occurred and recurred for months to years post-eruption. Lahar happens when erupted materials from a volcano are mobilized by rainfall. When ash and other volcanic debris flow with water, it becomes more erosive and can easily destroy any structure along its path. So many houses and lives were lost because of the lahar flows in the aftermath of Mt. Pinatubo’s eruption that even now, several lands are abandoned due to this hazard. Hikes and tours around Mt. Pinatubo are also prohibited during rainy season due to risks of lahar flows from the remobilization of volcanic materials along the slopes. In the video below, Dr. Renato Solidum, a geologist and undersecretary of PHIVOLCS, reminisced about the devastation during and after Mt. Pinatubo’s eruption.

Dr. Renato Solidum talks about the 1991 eruption of Mt. Pinatubo.

Video below is a half-hour shot of Mt. Mayon’s 2018 eruption, as it is spewing out lava and steam, shared by Expert Videos Channel in YouTube. While Mayon’s lava normally don’t reach the residential areas, fresh erupted materials are cause for concern because of the lahar flows that happen during rainy season. With Mayon erupting regularly at 2 year or so interval, this means that fresh volcanic materials are being deposited fairly regularly on its flanks which when mobilized by rainfall can result to lahar flows. Lahar flows, have in historic and recent past, destroyed developed and agricultural lands at the foot slope and along river banks.

And this was me with my friends when we went down one of Mt. Apo’s crater with active solfatara (sulfur-releasing crater) years ago. While Mt. Apo is considered an inactive volcano, this crater’s vents release plenty of sulfuric gas and then deposit the yellow crystal, sulfur, on the surrounding rocks. It smells like rotten eggs here due to sulfuric gas that we had massive headaches after. I know this may seem careless to all of you reading this article but we were careful not to go too near the vents. From what I heard, hikers are no longer allowed to go down this crater – and for good reasons too!

So nice to go back to the time we hiked Mt. Apo and visited its solfatara crater.

If you read this far, thank you so much. I will be posting more virtual geology lessons and tours like this in the future. If you have any topic request, let me know in the comments section.

Here’s a Story Map I made of our Volcanology Training in Mt. Mayon with Chris Newhall:

https://arcg.is/0rePKb0

xoxo

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