Geoscience That Made Headlines in 2018

By Erik Klemetti | December 28, 2018 11:38 am
Lava flows from the LERZ eruption of Kīlauea, seen in July 2018. USGS/HVO.

Lava flows from the LERZ eruption of Kīlauea, seen in July 2018. USGS/HVO.

2018 was quite a year across the geosciences … which is hardly shocking considering we live on the most geologically active planet in the solar system. Some of the events were tragic, because when it comes to headlines, that is what gets the most attention. Others were warnings of things that could be headed our way and others were, thankfully, downright exciting and uplifting. Here’s my quick takes on some of the big geoscience events from the year that was:

Lower East Rift Zone Eruption at Kīlauea

I suppose for a volcanologist like me, it would be hard to top the largest eruption in the United States since 1980. Not only that, the surprising eruption of Kīlauea from its Lower East Rift Zone (top) — the first in half a century —  dumped over 1 cubic kilometer of lava out and collapsed the summit of the Hawaiian volcano. Thankfully the eruption was free of fatalities and only had a few minor injuries. Unfortunately, many people in the lower East Rift Zone communities of Lelani Estates and Vacationland Hawaii lost the homes and livelihoods.

Indonesian Tsunamis

Indonesia was struck but multiple tsunamis in 2018, neither of which were caused by the same mechanisms that generated the 2004 Boxing Day tsunami. In September, a tsunami swept through parts of Sulawesi. This tsunami was likely caused by a submarine landslide triggered by an earthquake. The combined impact was over 2,200 deaths and tens of thousands of people made homeless, especially in the city of Palu.

This combination of synthetic aperture radar images taken by JAXA's ALOS-2 satellite and analyzed by Geospatial Information Authority of Japan shows Indonesia's Anak Krakatau volcano, center in images, before and after the Dec. 22, 2018, eruption. The images were taken on Aug. 20, 2018, left, and on Dec. 24, 2018, right, respectively. The satellite imagery showed a deformation on the volcano's southwest side. (JAXA - Geospatial Information Authority of Japan)

This combination of synthetic aperture radar images taken by JAXA’s ALOS-2 satellite and analyzed by Geospatial Information Authority of Japan shows Indonesia’s Anak Krakatau volcano, center in images, before and after the Dec. 22, 2018, eruption. The images were taken on Aug. 20, 2018, left, and on Dec. 24, 2018, right, respectively. The satellite imagery showed a deformation on the volcano’s southwest side. (JAXA – Geospatial Information Authority of Japan)

Just this month, a collapse of part of Anak Krakatau during an eruption triggered a tsunami in the Sunda Strait. Almost half of the volcano that grew inside the caldera formed by the massive 1883 eruption of Krakatau fell into the sea and the resulting tsunami has killed over 225 people so far. Since the collapse, the volcano has been producing explosive volcanic eruptions caused by magma interacting with seawater — something called Surtseyan-style eruptions.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

New Vent Erupts Lava and Ash on Italy’s Etna

By Erik Klemetti | December 24, 2018 8:14 am
The ash plume from Etna in Italy seen from the Catania Airport.

The ash plume from Etna in Italy seen from the Catania Airport.

A new vent opened today on Etna in Sicily with lava flows and an ash plume from the new vent near the Southeast Crater. The eruption started after over 100 earthquakes up to M4 rattled the volcano on December 24. People (mostly skiers) on the volcano were evacuated as the eruption began. The ash plume from the eruption prompted the airspace around Catania to close as well. From the look of the ash plume, some is being produced by the eruption but part of the plume may be coming from the interaction of lava and snow on the slopes of the volcano.

Today’s pass by NASA’s Aqua satellite got a shot of the ash plume from the eruption drifting to the southeast:

The ash plume from the December 24 eruption of Etna in Italy, captured by Aqua's MODIS imager. NASA.

The ash plume from the December 24 eruption of Etna in Italy, captured by Aqua’s MODIS imager. NASA.

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Surprise Tsunami Hits Indonesia, Killing Hundreds

By Erik Klemetti | December 23, 2018 8:01 am
Destruction from the December 23, 2018 tsunami in the Sunda Strait, Indonesia. BNPB.

Destruction from the December 23, 2018 tsunami in the Sunda Strait, Indonesia. BNPB.

For the second time this year, an unexpected tsunami hit the coast of Indonesia resulting in hundreds of deaths. This tsunami may have been generated by an eruption of Anak Krakatau in the Sunda Strait, with Indonesian officials speculating that an eruption that occurred late last night may have triggered undersea landslides. So far, at least 220 people are known to have died , over 800 were injured and multitudes are missing. Many of the deaths were in Pandelang, located at the end of bays that could have amplified the height of the waves. The tsunami waves were as high as 3 meters. You can see some of the destruction from these waves in the video and images below. UPDATE: The death toll is now over 400 and local authorities are asking people to stay off the beaches until midweek.

Whatever happened at Anak Krakatau to cause the tsunami, it appears that the volcano has experienced a major eruption as well. The Darwin VAAC report for the volcano indicate ash reaching as high as 17 kilometers (55,000 feet). The Himawari-8 weather satellite caught the plume from the eruption — you can see it in the false color loop:

UPDATE: Here’s another GIF showing last night’s eruptive plume from Anak Krakatau:

There are unconfirmed reports that the tsunami was generated by more than half of the existing Anak Krakatau cone collapsing into the sea. No significant earthquakes were recorded in the area last night, so the eruption of Anak Krakatau may be the likeliest source of the tsunami. There are some video that claim to be from after the eruption showing that does look like a dissected cone for the volcano:

UPDATE: Here’s another video from today of Anak Krakatau showing the strong “rooster tail” plumes being produced by magma interacting with seawater. It really does look like the island has changed significantly:

UPDATE: These images from Sentinel-1 show evidence of a collapse of Anak Krakatau along with potential waves generated by the collapse:

UPDATE: Apparently, this exact scenario was hypothesized in a 2012 paper by Giachetti and others. Hat tip to Jonathan Amos for that find.

UPDATE: Apparently the current eruption of Anak Krakatau has produced more volcanic lightning than possibly any eruption observed. Over 30,000 strikes since the eruption 2 days ago:

Sector collapse is one of the major ways that volcanic eruptions can produce tsunamis. An eruption of Unzen in 1792 caused part of the volcano to collapse into the sea, killing over 15,000. Krakatau, the volcano that preceded Anak Krakatau, famously produced a massive eruption and tsunami in 1883. Unlike this event, the 1883 tsunami that killed 36,000 was produced by a caldera collapse, where the entire volcano collapsed into itself forming a bowl that was filled by the sea (below). Anak Krakatau has been built over the past 125 years within that 1883 caldera.

Sentinel-2 image of Anak Krakatau erupting in September 2018. The three outer islands outline the shape of Krakatau prior to the 1883 eruption. NASA Earth Observatory.

Sentinel-2 image of Anak Krakatau erupting in September 2018. The three outer islands outline the shape of Krakatau prior to the 1883 eruption. NASA Earth Observatory.

As Simon Carn speculates, part of the volcano has grown rapidly over this year and Anak Krakatau has had an active fall, with frequent strombolian eruptions and lava flows – see the images above taken in September. One scenario [SPECULATION] is that a collapse of part of the volcano would allow seawater to interact with the erupting magma, causing the explosive eruption seen last night [SPECULATION] UPDATE: Simon Carn sees characteristics in the eruption that suggest a lot of magma and seawater interaction. Whatever the case, it may be a while before the full reason how the tsunami was generated.

You can watch some of the eruptions going on at Anak Krakatau only a few hours before the tsunami hit, taken by Øystein L. Andersen.

Øystein and his family escaped the tsunami (just barely) and he’s been updating with images of the aftermath of the tsunami.

I’ll add more information about this tragedy when possible.

CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Vote for the 2018 Pliny for Volcanic Event of the Year

By Erik Klemetti | December 20, 2018 1:52 pm
Agung in Indonesia erupting in November 2017.

Agung in Indonesia erupting in November 2017.

It’s that time of year to vote for the 2018 Pliny for Volcanic Event of the Year. We’ve had a lot of volcanic action worldwide this year and you can see some of the highlights in this compilation from the Atlantic or by checking out this year’s Weekly Volcanic Activity Reports from the Global Volcanism Program.

So, as usual, I look to you all to cast a ballot the Pliny. Send me (rockyplanetblog at gmail), tweet me (@eruptionsblog #2018Pliny) or leave a comment with your top 3 volcanic events for the year and I will compile the votes. Look for a post around the end of the year for a countdown of the most exciting and dangerous eruptions from the year that was.

Just to remind everyone, last year’s winner was Agung in Indonesia.

Other winners include

2009: Sarychev Peak, Russia
2010: Eyjafjallajökull, Iceland
2011: Puyehue-Cordón Caulle, Chile/Argentina
2012: Tolbachik, Russia
2013: Etna, Italy
2014: Holuhraun-Barðarbunga, Iceland
2015: Colima, Mexico
2016: Bogoslof, Alaska

Get voting! Ballots are due December 29!

CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Kīlauea’s 2018 Eruption Was the Largest in the United States for Almost 40 Years

By Erik Klemetti | December 12, 2018 10:15 am
Lava erupting on Kīlauea's Lower East Rift Zone during June 2018. USGS/HVO.

Lava erupting on Kīlauea’s Lower East Rift Zone during June 2018. USGS/HVO.

The 2018 eruption at Kīlauea was the largest in the United States since 1980. Between 0.8 and one cubic kilometers of lava poured out onto the surface of the Big Island of Hawai’i over the course of a few months, leading to massive destruction of property and infrastructure, but happily no loss of life. Much of that can be pinned on the excellent work done by the US Geological Survey and the Emergency Management teams in Hawai’i.

Although it has only been a few months since the eruption ceased, a team of USGS and other geologists have released a new paper in Science that discusses the events surround the remarkable eruption. The paper presents a clear description of all the events that happened from March to September, but the real meat of the paper deals with beginning to understand why the eruption happened and what the future might hold.

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Magnitude 7 Earthquakes Hits Near Anchorage

By Erik Klemetti | November 30, 2018 12:49 pm
Shake map for the M7 earthquake that struck near Anchorage on November 30, 2018. USGS.

Shake map for the M7 earthquake that struck near Anchorage on November 30, 2018. USGS.

Earlier today a M7 earthquake struck only 13 kilometers from Anchorage, Alaska. The earthquake was relatively deep, located ~40 kilometers beneath the surface. However, the city of Anchorage has experienced damage from the shaking. Anchorage airport has seen disruptions as the control tower was evacuated (and had been apparently running out of a truck). The FAA stopped flights in and out of Ted Stevens Airport as well.

UPDATE: The M7 earthquake was followed by a number of aftershocks, with the largest so far being M5.7. There has been significant damage in Anchorage, but luckily it seems like no tsunami was generated by the temblor. Many homes and roads have been damaged, but so far there have not been any reported deaths due to the earthquake. Over 30,000 people are without power as well.

This video shows the shaking that happened in Anchorage during the earthquake:

Also, rumors of potential “predicted” larger earthquake to follow are false (as are any places that claim they “predicted” it in the first place. You can read statement from the Alaska State Seismologist:

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

New Eruption at Alaska’s Veniaminof and Evacuations at Guatemala’s Fuego

By Erik Klemetti | November 21, 2018 2:15 pm
Image from the Perryville (Alaska) FAA webcam showing the plume from Veniaminof (dark cloud behind the antenna). FAA.

Image from the Perryville (Alaska) FAA webcam showing the plume from Veniaminof
(dark cloud behind the antenna). FAA.

Overnight, Alaska’s Veniaminof had its first eruption in a little over a year. An eruption plume reached 4.5 kilometers (15,000 feet) up and the plume was tracked spreading southeast for over 150 kilometers (90 miles). Visibility is low in the area of the Alaska Peninsula where Veniaminof is located, but the Perryville FAA webcam caught a glimpse of the dark grey ash plume (see above) this morning (Alaska time). The Alaska Volcano Observatory raised the alert status to Red after this new eruption started.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Are Big Earthquakes a Concern for the Eastern United States?

By Erik Klemetti | November 19, 2018 11:02 am
Damage from the August 31, 1886 earthquake near Charleston, South Carolina. John Karl Hillers/USGS

Damage from the August 31, 1886 earthquake near Charleston, South Carolina. John Karl Hillers/USGS

Most people who live in the eastern United States likely don’t worry too much about earthquakes. Most of the shaking that goes on across the country happens on the west coast, running up and down the San Andreas fault zone or in the Cascades of Oregon and Washington. Occasionally, an earthquake will rattle Yellowstone or Oklahoma feels an temblor brought on by waste water being pumped into the ground. But New York City? Boston? Charlotte? Washington DC? Other than the Virginia earthquake of 2011, most folks don’t even regard big earthquakes as an issue.

This is a tricky question to tackle because how rare large earthquakes tend to be in eastern North America. Trying to extrapolate how often earthquakes larger than magnitude 6 could occur typically involves examining the historical catalog. For parts of eastern North America, that might get us back 400 years. However, it really isn’t until the last 100 years that we have a good record of earthquakes that have been measured using seismometers. This means much of our knowledge of earthquakes on the east coast comes from historical records of large, noticeable events in places where people noticed them.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Campi Flegrei Is Warming Up, But We’re Likely Not Close to an Eruption

By Erik Klemetti | November 14, 2018 1:01 pm
The Bay of Naples in Italy, with the Campi Flegrei to the north (top) and Vesuvius to the east (right). Image taken 2002, NASA.

The Bay of Naples in Italy, with the Campi Flegrei to the north (top) and Vesuvius to the east (right). Image taken 2002, NASA.

First things first. This new article in Science Advances I’m about to discuss does not — I repeat, does not — say that an eruption will be happening soon at the Campi Flegrei in Italy. There is nothing in the paper that says we need to elevate the alert status or that anything fundamentally has changed about the current state of the caldera. So, nobody needs to panic.

Now that I have that out of the way, let’s actually talk science!

A new article that came out today in Science Advances by Francesca Forni and others tries to answer a question about giant volcanoes like the Campi Flegrei in Italy, namely where the volcano might be in a cycle of giant eruptions. The Campi Flegrei, possibly the most dangerous volcano on Earth right now, is the other very hazardous volcano along the Bay of Naples (the other being Vesuvius).

Most of the caldera is either under the bay itself or under the town of Pozzouli and within the caldera, there are some smaller volcanic vents. The last major eruption from the Campi Flegrei was the Neapolitan Yellow Tuff (NYT) that burst forth from the volcano ~15,000 years ago. This was preceded by an even bigger explosive eruption that happened ~39,000 years ago called the Campanian Ignimbrite, which may have had a hand in the downfall of the Neanderthals.

Those were the two big “super-eruptions” but since then, there have been a multitude of smaller event such as the formation of Monte Nuovo (literally, “new mountain”) that erupted in 1538. Since then, the Campi Flegrei hasn’t produced any eruptions but we’ve seen it behave like a “restless caldera“.

This means, much like Yellowstone in Wyoming, we’ve seen earthquake swarms, hydrothermal activity like steam vents and mudpots, and the land surface rise and fall, sometimes on the scale of meters. None of these events directly lead to an eruption, but instead betray events that are happening kilometers underground, where magma might be rising up from its source tens of kilometers down or where water in the crust above the magma might be heating up over time. Such is the life of a restless caldera.

So, the question that Forni and others posed is simple: are the recent eruptions such as Monte Nuovo a sign that the Campi Flegrei is still cooling down from the NYT or is it heating up, getting ready for its potential next big blast? This is a tough question because large eruptions don’t tend to happen in isolation and at many volcanoes, there is a cycle of eruptions (see below).

There are precursor eruptions that are much smaller as magma might “leak” from the source and there are “after-eruptions” that represent that leftover stuff from a big eruption. The lava erupted pre- and post-massive eruption tend to be geochemically different, so can we identify if the Campi Flegrei is currently in a cool down or warm up?

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Iceland’s Biggest Volcano is Restless, but That’s OK

By Erik Klemetti | October 26, 2018 11:09 am
Copernicus Sentinel-2B image of Öræfajökull in Iceland, seen in 2017. ESA- Antti Lipponen.

Copernicus Sentinel-2B image of Öræfajökull in Iceland, seen in 2017. ESA-
Antti Lipponen.

Over the past few days, news out of Iceland is that Öræfajökull, one of Iceland’s largest and most powerful volcanoes, is getting restless. The volcano is “accumulating magma” and an eruption was coming! It sounds bleak, doesn’t it? The volcano that produced the island’s largest known explosive eruption is showing signs that 291 years of relative quiet might be coming to an end. Even the most recent eruption that occurred in 1727 was a VEI 4, which is pretty large for an eruption. More importantly, the eruption caused multiple glacial outburst floods (jökulhlaups) that formed as the snow-and-ice cap on the volcano melted from the heat of the escaping volcanic debris.

So, should we be panicked? The answer is a resounding “no”. The evidence of Öræfajökull restlessness is a list of things that happen at many Icelandic volcanoes that aren’t necessarily heading towards an eruption in the near future (defined here as days to weeks, possibly months to years). This includes the snow-and-ice cap sinking in the middle of the caldera at the summit of the volcano over the past few years, likely a sign of heat within the caldera. There has also been deformation of the volcano itself as it “puffs out” like a balloon due to magma filling in underneath at a depth of ~ 5 kilometers beneath the surface. There has also been an increase in earthquakes at Öræfajökull over the past year, again most likely related to both magma intruding below the surface and changes to the hydrothermal system pumping water around near the surface as it heats up.

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CATEGORIZED UNDER: Eruptions, Science, Science Blogs
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Rocky Planet

Rocky Planet covers all the geologic events that made and will continue to shape our planet. From volcanoes to earthquakes to gold to oceans to other solar systems, I discuss what is intriguing and illuminating about the rocks beneath our feet and above our heads. Ever wonder what volcanoes are erupting? How tsunamis form and where? What rocks can tell us about ancient environments? How the Earth might change in the future? You'll find these answers and more on Rocky Planet.
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