Guest Videos: Nyiragongo’s Lava Lake

Molten rock at Kilauea’s summit has disappeared from view, but the world’s largest lava lake is still bubbling away in the crater of Africa’s Nyiragongo Volcano.

The tricky part is getting down there to check it out.

It isn’t easy for tourists to approach Nyiragongo’s summit, either.

But the fascination of that incandescent glow is intense.

More information:

Smithsonian Global Volcanism page


OSU article on “The Most Dangerous Volcano in the World” (videos of Hawaiian lava flows aren’t from 2018)

Photovolcanica: Nyiragongo

If Twitter Was Around When Mount St. Helens Blew

It’s wonderful (from a distance) to follow the ongoing eruption at Kilauea via the Web. Twitter is especially helpful.

I’ve been wondering what the 1980 reawakening and eruption of Mount St. Helens would have been like on Twitter. Here are some tweets I’ve found from volcanologists and other interested people who have not forgotten May 18, 1980, as well as a movie from the National Archives.

Continue reading

Guest Video: Volcanologist v. Volcano

The best background to read for this video is in the book Volcano Cowboys.

The short version: this is volcanologist David Johnston (and an equally crazy coworker) walking in the heart of a pre-eruption Mount St. Helens on April 30, 1980, for samples. They really needed the samples, but this was something beyond dangerous to do.

The volcano allowed it to happen on that day . . .

. . . and then on May 18th killed Dr. Johnston, who was manning a USGS observation point about five miles from the crater, in a direct line with the lateral blast, as well as over fifty other people. Until that day, volcanologists didn’t know that volcanoes can erupt sideways so violently.

It was a costly lesson, but the death toll would have been much higher if Johnston and his colleagues hadn’t issued and maintained a very controversial no-go order for vicinities near what everyone called “America’s Mount Fuji” until it erupted.


Source, CC BY-SA 3.0.

Caption: Source, CC BY-SA 3.0.

Kirishimayama Volcano Group


For most of us, the words “Japan” and “volcano” summon up an image of Mt. Fuji, near Tokyo. But this country has many more volcanoes, some of them not as simple in appearance as Fuji-san.

Take Mount Kirishima, for instance. It is a study in contrasts.


Not least because it rises out of townlands and has a lot of vents. (Jun Seita, CC BY 2.0)

On the one hand, Kirishima frequently erupts; on the other, it’s a great place for a walk through the park.

A violent history

Starting some 600,000 years ago, huge caldera-forming eruptions began here, at the head of Kagoshima Bay on the island of Kyushu. Ever since then, volcanic events have been explosive in nature (not showing much runny “Hawaiian-style” lava).

About 330,000 years ago the style changed to building stratovolcanoes instead of big holes in the ground (which is what a caldera is, basically). Ever since, this complex volcano has built more than 25 relatively small peaks and cones. Two vents are currently erupting: Shinmoedake and Ioyama.

Occasionally magma interacts with ground water, forming a maar with the resulting steam-driven eruption.

The park

Here is someone’s video of a walk up three volcanoes in the area; the first two–Takachiho (crowned with a legendary spear, per Wikipedia) and Karakuni–are part of the Kirishima center; the last one, beautiful Kaimon, belongs to the Ata caldera underneath Kagoshima Bay.

That certainly looks peaceful. Volcanoes sculpt some of the most beautiful landscapes in the world. But as you can see, a lot of people live near Mount Kirishima.

This volcanic group is slowly becoming more active and its magma rate is increasing. Volcanologists are watching Kirishimayama closely to better understand how it works so they can most accurately predict its future course.

Featured image: NASA Earth Observatory.


Global Volcanism Program. 2018. Kirishimayama.

Nagaoka, S., & Okuno, M. 2011. Tephrochronology and eruptive history of Kirishima volcano in southern Japan. Quaternary International, 246(1-2): 260-269.

Mount Rainier

This was first published at my other blog on May 3, 2014.

There is a king in the Pacific Northwest, his brow crowned in glittering ice.

Mount Rainier starts to rise only about 25 miles from the Seattle-Tacoma metropolitan area. Today this beautiful Cascades stratovolcano, towering 14,410 feet above Puget Sound, dominates the skyline of towns and cities that sit on material that once made Rainier almost 2000 feet taller.

Flank Collapse

About 5600 years ago, around the time when the ancient Egyptians were getting organized, Mount Rainier’s northeast flank and summit collapsed. It was dramatic even as described by scientists, who say that a cubic mile (4 cubic kilometers) of flank and summit material (now called the Osceola Mudflow):

…washed across Steamboat Prow and Glacier Basin and then ran up to about the 6400-foot level of Goat Island Mountain and Sunrise Ridge. It then descended the White River valley 80 to 150 m (260- 490 ft) deep, spread out over 210 km2 (82 mi2) of Puget Sound Lowland 70-100 km (44-62 mi) from source, and flowed into Puget Sound, moving underwater up to 20 km (12.4 mi) to the present sites of Tacoma and the Seattle suburb of Kent. The contemporaneous phreatic and phreatomagmatic explosive eruptions blew hydrothermal clay and mud northeastward across Sunrise Ridge and spread pumice across an arc from south to northeast of the volcano. The Osceola edifice collapse left a horseshoe-shaped crater open to the northeast at Mount Rainier, much like the open crater formed at Mount St. Helens in 1980.

Mount St. Helens composite image by Ewen Roberts

Mount St. Helens composite image by Ewen Roberts.

Geologists believe that this collapse happened because the rock had been weakened by the circulation of hot, acidic water inside the volcanic structure. Over time, through many eruptions, Rainier built itself back up into the majestic but dangerous structure everyone today knows and loves.

The USGS says it has seen no change in the pattern and expects Rainier to continue growing, erupting and collapsing.

Volcanic Hazards

Today, about 80,000 people are at risk from a potential mudflow, also known as a lahar, from Mount Rainier, say experts at the United States Geological Survey (PDF). This could be triggered by the sort of volcanic activity that the USGS monitoring network would pick up, but it might also happen without warning as another flank collapse. Such a collapse, say the geologists, could reach Orting, Washington, in as little as 40 minutes.

For this urgent need, an acoustic network now surrounds Rainier. Pierce County, Washington, also is developing a specific volcanic hazard plan (PDF) for Mount Rainier.

No one wants to live in fear when there is so much beauty and wonder about this monarch of the Cascades. Having recognized its dangers, people are working to minimize them so that everybody can continue to enjoy this beautiful mountain.. This requires a lot of work but, as shown in Jayson Yogi’s video of a 2011 Rainier summit climb via the Emmons Glacier, difficult struggles have their own special rewards.

Update, July 17, 2014: “Detailed imaging of Mount Rainier shows subduction zone in glorious detail.” Scott Johnson, Ars Technica.

Front Page Image of Mount Rainier is by Michael Lehenbauer.


Mount Rainier,” United States Geological Survey: Volcano Hazards Program.

“Mount Rainier – Living Safely With A Volcano In Your Back Yard.” (PDF) USGS Fact Sheet 2008-3062

Timeline — B.C.” Air War College: Contents of 12,000 Year Timeline.

“Volcanoes of the Cascades: Their Rise and Their Risks.” Richard L. Hill. Globe Pequot Press, Guilford, Connecticut. 2004.

Guest Video: New Mexico’s Volcanoes

Rifting in this region happened because of a complex series of events, called the Mid-Tertiary Ignimbrite Flareup, many tens of millions of years ago. During this tumultuous time volcanism was extreme throughout what are now the western United States and northern Mexico.

Things obviously have quieted down since then, but geoscientists are still keeping an eye on the southwestern US. Researchers study a magma body miles below the city of Socorro, while the US Geological Survey is aware of such potential problem sites as the Zuni-Bandera volcanic field and Valles Caldera.

Guest Video: Villarrica Volcano

Almost sixty eruptions have been documented at this Chilean volcano since Europeans first saw it erupting in 1558.

Villarrica is a classic stratovolcano–the pointy kind – and is one of a group of Southern Andes volcanoes.

Per the volcano’s GVP page, the lava lake has been there intermittently since the mid-1980s.

Since the eruption style has been Strombolian (occasional brief “shots” rather than a sustained lava flow or explosive phase), it’s a little more approachable than some active volcanoes.

Despite the obvious dangers, Villarrica attracts daredevils who bungee a tolerable distance into the crater from a helicopter or do this —

Villarrica is monitored by both Chile (Spanish) and a private group. (Spanish)

Lahars (mud flows) from this volcano killed a hundred people during the 20th century. Other dangers include projectiles – something people soaring or hanging over the crater are especially at risk for in addition to the poisonous gases, heat, and chance eruption cloud. Lava flows also happen at Villarrica and, less frequently, pyroclastic flows.

Featured image: Cristian Gonzalez G. CC BY-ND 2.0.

Caribbean Plate Volcanoes: The Central American Arc

The Caribbean tectonic plate gets little respect. This is probably why it lashes out so violently at times in earthquakes and volcanic explosions.

First, most of this relatively small chunk of Earth’s lithosphere is underwater, so hardly any of us even know it’s there.

Then North America jostles it from the north, messing up its boundaries, while South America does the same thing to the south. East and west, seafloors on other plates dive underneath the Caribbean plate’s edge in subduction zones and then melt upward through it to form explosive volcanic arcs.

These are the Lesser Antilles island arc in the east and the land-bound Central American Volcanic Arc to the west.

This post is about those Central American volcanoes–well, not all of them. There are hundreds of stratovolcanoes, lava domes, and cinder cones in this group.

Let’s break it down by country.

Guatemalan volcanoes

Here are a just a few of the 300+ vents in this small nation.

Monitoring: INSIVUMEH. (Spanish)

Risk: High, obviously. In fact, only Indonesia has more people living near active volcanoes. (Ewert and Harpel) According to one source:

The highest risk is located around the vents of Almolonga and Santa Maria, due to the very large population living within 10 km of the volcanoes and also the high VEI 6 figure for Santa Maria as designated by the Global Volcanism Program. The areas to the south and east of Fuego are also designated high risk due to the numerous hazards that combine and overlap within these areas, from hazards generated by Atitlan and Acatenango.

Biggest known eruption: That 1902 VEI 6 event at Santa Maria, in which thousands of people died, was the second largest eruption of the 20th century (the largest one, in 1912, happened in Alaska).

And then there was the VEI 7 caldera eruption at Atitlán during the last ice age some 85,000 years ago. Today a lake fills the caldera left by this “Los Chocoyos eruption,” and “normal”-sized eruptions at one of the three stratovolcanoes on the calderas rim are the norm.

El Salvador

This is the country where cameras caught the start of an eruption at Chapparastique Volcano, the most active of some 20 or so El Salvadoran volcanoes. You might have seen the video:

Monitoring: SNET. (Spanish)

Risk: High.

Biggest known eruption: A few high-end VEI 6 eruptions and one VEI 7 are listed.

Also, a VEI 6 caldera eruption at Ilopango, which sits right next to the country’s capital city, happened in the fifth or sixth century AD.

Besides devastating the Maya politically and economically, as well as socially, this “Tierra Blanca Joven eruption” may have caused climate effects and hardship elsewhere in the world, and possibly even contributed to the Justinian Plague! (Oppenheimer)


There are at least 19 volcanoes in this country, and some of them are popular tourist destinations.

Monitoring: Hard to say. The link given at WOVO doesn’t work.

Risk: Per this abstract, there are a variety of risks.

They don’t mention gas, probably because that is a common (and very dangerous) volcanic hazard everywhere:

Biggest eruption: Both Apoyeque and Masaya have had VEI 6 eruptions, though not any time recently; Masaya’s eruptions are usually less intense.

Costa Rica

This country’s beautiful string of volcanoes draws a lot of tourists.

It is quite a beautiful country.

Monitoring: OVSICORI-UNA. (Spanish)

Risk: High.

Biggest eruption: An unexpected VEI 3 eruption at Arenal in 1968 killed 87 people, per Wikipedia. Also, a few Costa Rica volcanoes, including the Barva complex, Miravalles, and Poás have VEI 6 or 7 eruptions listed in the distant past.


Wait, Panamá has volcanoes? Yes, at least three of them.

Monitoring: The National Civil Protection System, apparently. They responded to what turned out to be false concerns in 2015 that Barú was going to erupt.

Risk: Barú is the youngest and most recently active volcano, so most attention focuses on it.

Biggest eruption: El Valle had a VEI 4 ignimbrite eruption about 56,000 years ago, though it has been quiet ever since.

By now, you have probably forgotten the poor Caribbean plate–no respect–but it’s still there, underneath all these Central American lands, interacting with various microplates that lay between it and the huge Pacific tectonic plate.

Let’s close by standing atop Barú volcano – the only place in the world where, thanks to the narrowness of the Panama isthmus, you can see the Atlantic (on our right) and the Pacific (left) oceans at the same time.

Featured image: Central America volcanic front. CrazyKnight. CC BY-SA 3.0.


Bachmann, R. 2001. The Caribbean plate and the question of its formation. Institute of Geology, University of Mining and Technology Freiberg Department of Tectonophysics

Ewert, J. W., and Harpel, C. J. 2004. In harm’s way: Population and volcanic risk. Geotimes. Last accessed March 18, 2018.

Giunta, G. and Orioli, S. 2011. The Caribbean Plate Evolution: Trying to Resolve a Very Complicated Tectonic Puzzle, New Frontiers in Tectonic Research – General Problems, Sedimentary Basins and Island Arcs, ed, Sharkov, E. InTech, DOI: 10.5772/18723. Available from:

Oppenheimer, C. 2011. Eruptions That Shook The World. Cambridge: Cambridge University Press. Retrieved from

Caribbean Plate Volcanoes: The Lesser Antilles

It’s not hard to grasp the basic idea of plate tectonics: There’s a crack in the middle of the ocean floor where magma rises from deep within the planet, forming two seafloor halves that spread apart.

And if we were flat-landers, that would be that. However, the whole thing happens on round and curvy Earth, so plate interactions can get complicated–but also very interesting.

Take the Caribbean plate, for instance–the floor of the Caribbean Sea, south of the Gulf of Mexico, and the land masses around it (including much of Central America).

No one is quite sure how this minor plate formed up through the end of the dinosaur age, but watch how it moves in this elegant, multi-million-year-old dance:

Certainly the Atlantic fits our stereotype of “big crack,” two sides spreading apart for many tens of millions of years in the past (and this likely will continue for far longer into the future than any of us need to consider). But there is a lot more going on in the Caribbean.

And it involves volcanism and earthquakes, both of which are capable of kicking up a tsunami in this part of the world.

The eastern and western ends of the Caribbean plate are currently the most active. In honor of this week’s change in the status of Kick-’em-Jenny volcano near Grenada, let’s start with the eastern side – the Lesser Antilles island arc.

Why are there volcanoes, and accompanying earthquakes, there? The University of the West Indies Seismic Research Centre knows.

Sunday Morning Volcano posts at my other blog on some of these volcanoes include:

That’s only a few of the many Caribbean volcanoes.

Next time we’ll look at volcanoes on the western edge of the Caribbean plate, including one whose eruption may have affected the fate of the Eastern Roman Empire (and certainly affected the nearby Mayan Empire) and another whose Ice-Age eruption may have been big enough to qualify as “super.”

Featured image: Eastern Lesser Antilles (Barbuda to Grenada), Jacques Descloitres, MODIS Rapid Response Team, NASA/GSFC, via Wikimedia.


Allen, R. W.; Berry, C.; Henstock, T. J.; Collier, J. S.; and others. 2018. 30 Years in the Life of an Active Submarine Volcano: A Time‐Lapse Bathymetry Study of the Kick‐‘em‐Jenny Volcano, Lesser Antilles. Geochemistry, Geophysics, Geosystems.

Bachmann, R. 2001. The Caribbean plate and the question of its formation. Institute of Geology, University of Mining and Technology Freiberg Department of Tectonophysics

Giunta, G. and Orioli, S. 2011. The Caribbean Plate Evolution: Trying to Resolve a Very Complicated Tectonic Puzzle, New Frontiers in Tectonic Research – General Problems, Sedimentary Basins and Island Arcs, ed, Sharkov, E. InTech, DOI: 10.5772/18723. Available from:

Macdonald, R.; Hawkesworth, C. J.; and Heath, E. 2000. The Lesser Antilles volcanic chain: a study in arc magmatism. (Abstract only) Earth-Science Reviews. 49(1-4): 1-76.