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Earth Matters

For more than two months, lava has been pouring from part of Hawaii’s Kilauea volcano, destroying homes and remaking the land surface. More data and imagery of the eruption is flowing in from satellites, drones, and ground-based sensors than Earth Observatory can cover, but here are a few striking images that we would be remiss not to share.

By The Lava’s Early Light
NASA Astronaut Ricky Arnold tweeted this nighttime photograph of lava on June 20, 2018. If the Star Spangled Banner had been composed in Hawaii rather than Baltimore, maybe “lava’s early light” would have made it into the lyrics. Credit: NASA


The Wrong Side of the Lava Flow


Notice the stark differences in landscapes on the northern and southern sides of the lava channel. With trade winds blowing heat and volcanic gases to the southwest, the north side remained green. Vegetation on the south side, yellowed and brown, took a battering. This aerial photograph was taken on July 10, 2018. Image Credit: USGS.


A Colorful Satellite Perspective on a Collapsing Caldera

As lava flows from some parts of Kilauea, other parts of the volcano have been sinking. In the case of the summit caldera, the rate of subsidence has been dramatic. This interferometric synthetic aperature radar (InSAR) image, or interferogram, shows surface movement at the summit caldera between June 9 and June 23. Each cycle of yellow-blue-purple indicates approximately 5 inches (13 centimeters) of movement. Areas where the colorful lines are the closest have shifted the most. The data was collected by Advanced Land Observing Satellite-2 (ALOS-2), a Japanese Aerospace Exploration Agency (JAXA) mission. Read more about this image and type of data from NASA’s Disasters Program. Image Credit: NASA/JAXA.

The Same Caldera Collapse Seen from the Ground


This sequence of images shows rapid subsidence of the caldera floor, along with the development of scarps. One photograph is shown per day between June 13 and 24. The photos were taken from the southern caldera rim, near Keanakāko‘i Crater, and face north. Image Credit: USGS.


Laze Billows into the Air as Lava Pours into the Sea


In this Sentinel-2 image,  a large plume of laze—steam, volcanic gases, and shards of glass—blows west over Hawaii as lava poured into the sea on June 27, 2018. Pierre Markuse created this image using data from Sentinel-2, a satellite managed by the European Space Agency. He regularly downloads and processes Sentinel and Landsat satellite data and has posted dozens of Kilauea images on Flickr. Image Credit: ESA/Sentinel-2/Markuse

Blizzard 2017: Not In Denver, but in Hawaii

March 10th, 2017 by Pola Lem

In Hawaii, land of palm trees, pineapples, and year-round surfing, a full-blown blizzard hit last week. The early March storm brought more than 8 inches (20 centimeters) to the top of Mauna Kea volcano, leading authorities to shut the road to the peak.

The snow was all the more surprising given how little has fallen in more traditionally snowy locales. Hawaii received more snow that day than Denver has accumulated over the past seven weeks. The Colorado city got 1.6 inches (4 centimeters) in the past 51 days, according to local news.

The island archipelago also got more white stuff than Chicago. That city, famed for its bitter winters, is currently in the midst of a snow drought, with a mere 0.6 inches (1.5 centimeters) falling in 2017. That’s the least on record since the late 1800s. To put that into perspective: Chicago averages 37 inches (94 cm) of yearly snowfall. By contrast, Hawaii gets a yearly average of 3.7 inches (9 cm).

Thanks to their height, the peaks of Mauna Kea and Mauna Loa volcanoes do receive a dusting now and again. But that snow rarely sticks around for more than a few days, according to Ken Rubin, an assistant professor of geology and geophysics at the University of Hawaii.

Mauna Kea in December 2016. Image: NASA Earth Observatory/Jesse Allen, using Landsat data from the U.S. Geological Survey.

 

A Shape-Shifting Volcanic Island

February 2nd, 2017 by Kathryn Hansen

Image courtesy of AVO/USGS.

Looking at Earth from space every day, we notice that nature takes on some curious shapes. (We have found, for example, features that resemble every letter of the alphabet.) The landform in the image above, which looks a lot like a human ear, is actually Bogoslof Island—a volcano in the Bering Sea that has been erupting in recent weeks. But the island didn’t always have an ear-like shape, and it might not look that way in the future.

Bogoslof has been erupting since mid-December 2016. We wrote about it a few weeks ago when satellite imagery showed a plume of steam and ash ejected from the volcano’s vent. Much of the volcano was (and remains) under water, with only a small part of the volcano’s top rising above the surface. Interaction of the vent with seawater was the reason that the plume contained so much steam. But by the end of January 2017, things had changed. The image above, from the Alaska Volcano Observatory (AVO), shows the island’s new shape after an eruption on January 30-31.

The image was described in more detail by Dave Schneider on the AVO website:

“Freshly erupted volcanic rock and ash have formed a barrier that separates the vent from the sea. This is the first time this has been observed since the eruptive sequence began in mid-December 2016. The vent is below sea level, and erosion of the ash deposits by wave or eruptive processes would allow sea water to flow into the vent again.”

Find more information and images describing Bogoslof and its changing form here.

Something Swirling in the Sea

January 20th, 2017 by Kathryn Hansen

Almost every volcano is interesting from a scientific perspective, but there are just too many eruptions for us to cover every single one. Instead we tend to focus on eruptions that have the potential to affect people. Or, occasionally our satellites return images that simply look so unique that we find the time to cover them. The plume recently ejected from Alaska’s Bogoslof Volcano was noteworthy for both reasons.

Bogoslof, which has been erupting since mid-December 2016, gave rise to a compelling two-tone plume. Are materials being ejected from a vent that is still under water? (Most of the volcano is below the surface of the sea.) The volcano’s interaction with seawater explains the white steam. But if the vent is not yet above water, then how did such a large, dark plume of ash reach so high in the atmosphere? Scientists at the Alaska Volcano Observatory continue to monitor the remote volcano and perhaps answers will be forthcoming as the eruption evolves.

Also intriguing are the swirls of blue visible in the image above. The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured the image on January 7, 2017. My first thought was that the color was caused by a bloom of phytoplankton. The milky blue color looked about right. And iron from eruptions have previously been shown  to provide the nutrients needed for blooms to flourish. But when I asked the experts, the general consensus was that while you can’t rule out a bloom, there was another more likely explanation for the swirls.

According to ocean scientist Norman Kuring of NASA’s Goddard Space Flight Center:

“Phytoplankton don’t normally bloom in the Bering Sea during winter because there’s not a lot of sunlight and because winter storms deepen the mixed layer which also keeps the plankton more in the dark. Wave action can resuspend bottom sediments, and that may be happening farther east along the Aleutian chain in the January 7 image where the water is relatively shallow. Bogoslof Island is beyond the shelf break, however, so bottom resuspension is less likely. Ash in the water seems most probable…. I wouldn’t expect the Bering Sea to be nutrient limited in the winter, so I don’t expect an ash-based phytoplankton boost.”

In short, the swirls are probably ash in the water. The phenomenon is not unprecedented. We have previously published images of the occurrence here and here. But as Kuring reminds us, “the only way to know for sure would be to sample the water directly.”

 

Parade of Volcanoes

January 17th, 2012 by jallen

It’s been a really active time for the Earth Observatory and volcanoes. In the past three weeks, we’ve posted images of a night-time eruption of Shiveluch, ongoing activity at Puyehue–Cordón Caulle, daytime activity at the Kizimen Volcano, and my own favorite, a brand new island in the Red Sea. And those are just the images we published!

In recent weeks, we had a good shot of activity at Kilauea, but we skipped it since it only had Halema’uma’u activity — which is much like previous images and not the new ocean entry point, which we’ve yet to glimpse in cloud-free satellite imagery. We received an excellent ALI scene of the submarine El Hierro volcano (which we published) and then the next day we received an image of the same volcano from Landsat 7  (which effectively got scooped by ALI).

Another of the moderately recent and interesting images of volcanoes we didn’t use is a very nice ALI shot of the Cerro Hudson volcano in Chile.

We do have a good reason for not using the image. Notice the volcanic activity? Yeah, we didn’t see anything either. What makes this image interesting (to me anyway) is that just two weeks earlier, it looked like this:

We did publish that one. There’s actually not much in the way of activity in that one either, but in the published image, you can see a lot of ash that’s fallen on the ground from activity in October at the volcano.

Just two weeks later, with no new activity, almost all the ashfall seems to have “disappeared.” Fresh snow fell and covered much of it. Also, we got a much better shot with ALI of the volcano, getting a very nice view of the entire caldera, the glacier draining it out of the northeast, and forests in the alpine valleys. The ashfall was nowhere near as extensive and damaging as the Puyehue eruption, which at one point spewed out ash that circled the globe.