December 10th, 5:00 am

USGS Volcanoes

This Monday, #Yellowstone #CalderaChronicles takes a closer look at last year's Maple Creek earthquake swarm

volcanoes.usgs.gov/volcanoes/yellowstone/article_home.html

In June of 2017, an earthquake swarm began beneath the western edge of Yellowstone National Park, just east of Hebgen Lake. This swarm proved to be one of the more persistent swarms observed in Yellowstone, with the main episode lasting more than 3 months and producing thousands of recorded earthquakes. Most of the earthquakes were very small, but a few were felt in the park, including the largest, a magnitude 4.4 earthquake on June 16, 2017.

Because of investments made in upgrading the seismic network over the past several years, this swarm was captured in more detail than any previous large swarm in Yellowstone. This means that scientists, including those involved in YVO, have more data than ever to detect and precisely locate earthquakes in the swarm, which can provide evidence of the causes of seismic swarms in the area.

Using a research technique that involves directly comparing the waveforms of the thousands of recorded earthquakes (instead of the routine processing that detects and locates earthquakes individually), scientists can greatly improve the precision of earthquake locations. Not only that, but we can also detect and locate thousands of earthquakes that were too small to be readily located as individual events (most of these earthquakes are less than M1.0. The patterns of seismicity from the swarm in time and space that have been revealed from this processing are striking—the swarm involved numerous fault structures over its course. Many of these faults are parallel and oriented along east-northeast trends, but some faults with orientations that are nearly perpendicular to that trend were also activated. Over the 3 months of the swarm, seismicity migrated outward from its initial activation area, both laterally and in depth. At times, this migration was rapid; at other times it was slow.

What do these patterns tell us about the physical processes driving the swarm? Although movement of magma can sometimes generate earthquake swarms at volcanoes, the patterns of this swarm (especially the rapid migration and lack of nearby surface deformation) instead suggest that water is diffusing through small cracks in the subsurface. The involvement of this water may in part explain why these swarms are sometimes long-lived, why they expand dramatically over time, and why the fault structures are so complex. This also may explain why swarms are common in volcanic areas, where water is a byproduct released from deeper magma as it cools. We often see chemical evidence for this type of water at surface springs and fumaroles.

Because this water is under great pressure in the deep crust where it is released, it tends to migrate upward and sometimes laterally. When it interacts with cooler, more brittle rocks stressed by tectonic and volcanic processes, this water may trigger earthquakes. In fact, earthquakes themselves may allow the fluid to migrate more efficiently, through faults in the rock.

Without of other signs of volcanic unrest (like rapid surface deformation or changes in gas emissions), earthquake swarms probably do not indicate increased volcanic hazard. Although the 2017 Maple Creek swarm was a larger-than-average example, and therefore garnered significant public and scientific interest, earthquake swarms such as this likely reflect ongoing low-level tectonic and volcanic processes in Yellowstone. Even though this swarm might be “business as usual” for the caldera, the outstanding monitoring systems at Yellowstone provide an exceptional window into this “business,” which will allow us to better understand future earthquake swarms not only at Yellowstone but also at other volcanoes around the world.

(Plot shows evolution of the 2017 Maple Creek earthquake swarm, with earthquake locations colored by time. a) Map view. b) West-east cross-section. c) Three-dimensional view, looking from the east-southeast, along the axis for much of the swarm activity.)
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December 8th, 4:32 am

USGS Volcanoes

Record breaker!!!

Today (December 8), at 1:07 AM local time, #Steamboat geyser in Yellowstone National Park erupted, marking the 30th major water eruption of 2018. This breaks the previous record for major eruptions in one calendar year, set in 1964.

(Photo: Steamboat geyser eruption of June 4, 2018. Photo by Jamie Farrell, University of Utah.)

#YVO #Yellowstone
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December 7th, 12:57 pm

USGS Volcanoes

All volcanoes in the Cascade Range of Washington and Oregon are at normal background levels of activity this week.
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Weekly Update: on.doi.gov/2hwAiRm

Field crews took advantage of sunny (but chilly) weather to do maintenance on the monitoring networks at Mount St. Helens, Newberry, and Three Sisters. This December 6, 2018 image, is of Mount St. Helens, view to the east, with Coldspring Creek in the middleground. USGS image taken by Kurt Spicer.

#usgs #cvo #cascadesvolcanoobservatory #volcanoupdate
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December 7th, 8:29 am

USGS Volcanoes

Ninety days with no lava: ready to call it quits?

Over the last several weeks, one of the most frequently asked questions of USGS Hawaiian Volcano Observatory (HVO) scientists has been, "is the eruption over?"

It has now been over three months since the lava inside the fissure 8 cone drained away (September 4). The Smithsonian Institution's Global Volcanism Program (GVP) (volcano.si.edu/) classifies the end of continuous volcanic activity as being an absence of eruptive activity over a three-month period. So, using this GVP criterion and no signs of imminent unrest on Kīlauea, the LERZ eruption could be considered over.

But for HVO scientists, the work continues. Magma is still being supplied to Kīlauea Volcano and geophysical datasets continue to show evidence for movement of molten rock through the magmatic system, including the refilling of the middle ERZ. It’s important to note that Kīlauea is still an active volcano that will erupt in the future and associated hazards have not changed. When a new eruption does occur, ground cracking, gas emissions, seismicity, and deformation can rapidly change.

HVO continues to closely monitor Kīlauea Volcano through ground-based observations, helicopter overflights, and geophysical instrument networks. Significant changes will be noted in HVO’s weekly updates, volcanoes.usgs.gov/volcanoes/kilauea/status.html

Read more in the latest edition of HVO’s Volcano Watch, volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?vwid=1394\

The webcam image is a view into the fissure 8 cone in Kīlauea Volcano's lower East Rift Zone from November 4, 2018. Webcams are available at volcanoes.usgs.gov/volcanoes/kilauea/multimedia_webcams.html.

#usgs #hvo #hawaiianvolcanoobservatory #kilauea
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December 3rd, 10:22 am

USGS Volcanoes

#Yellowstone #volcano monthly update
December 3, 2018, 1:13 PM MST
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

volcanoes.usgs.gov/vhp/updates.html#yvo

RECENT WORK AND NEWS

Steamboat geyser seems to have settled in to a pattern of near-weekly water eruptions, with activity on November 7, 15, 21, and 28. There have now been 29 total Steamboat water eruptions in 2018, which ties the record for the most eruptions in any given calendar year (previously set in 1964). Researchers took advantage of the temporary seasonal Park closure in early November to conduct field work in the Upper Geyser Basin, including the recovery of seismic sensors from around Geyser Hill (which were installed to monitor activity that commenced in mid-September), collect sinter and tree-ring samples to investigate past hydrothermal activity, and to study the biology of hydrothermal waters in the region.

SEISMICITY

During November 2018, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 126 earthquakes in the Yellowstone National Park region. The largest event was a minor earthquake of magnitude 2.4 located 15 miles north of West Yellowstone, MT, on November 4, at 10:11 AM MST. This earthquake is part of ongoing seismicity in that area (site of last year's 3-month-long Maple Creek swarm), which includes a swarm of 57 located earthquakes that started on November 4 and lasted throughout the month.

A second swarm of 22 earthquakes occurred November 21-24 (MST). The largest swarm event, a minor earthquake of magnitude 2.3, was located 16 miles south-southwest of Mammoth, WY, on November 23, at 09:25 AM (MST), .

Earthquake sequences like these are common and account for roughly 50% of the total seismicity in the Yellowstone region.

Yellowstone earthquake activity remains at background levels.

GROUND DEFORMATION

Surface deformation recorded by GPS stations within Yellowstone caldera continues to be characterized by ground subsidence at rates of a few centimeters per year. In the area of Norris Geyser Basin, GPS data indicate no significant deformation. Uplift there, which has been occurring at an average rate of a few centimeters per year since 2015, seems to have paused for the past ~2 months. A similar pause occurred at about the same time of year in 2017 and may therefore represent a seasonal affect.

(Photo: Silex Spring, Lower Geyser Basin, Yellowstone National Park)

#YVO #USGS
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December 3rd, 5:00 am

USGS Volcanoes

#Yellowstone #CalderaChronicles this week describes the chemistry of Yellowstone Lake -- and the hot springs that lie beneath the pristine waters!

volcanoes.usgs.gov/volcanoes/yellowstone/article_home.html

When you think of a lake bed, what comes to mind? Squishy bottom with some grasses, rocks, and sunken logs? Well, the floor of Yellowstone Lake has hot springs, sinter deposits, altered muds, heat-loving bacteria, rocky siliceous spires, and hydrothermal explosion craters. These features have been the subject of intense study over the last 20 years, and research results show that the springs have an impact on the chemistry of the lake itself.

Yellowstone Lake is a large and pristine high-altitude fresh-water lake that is up to 130 m (430 ft) deep. The lake is irregular in shape covers an area roughly 27 km (16 mi) long (north-south) and 21 km (13 mi) wide (east-west). The northern half of the lake sits within the Yellowstone Caldera, which formed 631,000 years ago. The magma storage region several kilometers below the caldera provides heat that circulates the hot fluids that feed the lake-bottom hydrothermal features. Hot springs on the lake floor are typically in the 30-100°C (86-212°F) range, but boiling temperatures increase with depth due to increased pressure associated with the overlying water column. The maximum boiling temperature on the deepest part of the lake floor is about 180°C (356°F).

To understand the contribution of hot springs to chemicals in the lake, a team led by USGS scientist Laurie Balistrieri in 1998-2003 collected and analyzed water samples from streams flowing into the lake, from the water in the lake, and from hydrothermal vents. Calculations indicate that Yellowstone Lake water is substantially enriched in some elements compared to the waters that flow into the lake. This means lake-bottom hot springs substantially affect water chemistry.

Studies by USGS scientists Bob Fournier and Irving Friedman and their associates have shown that the chloride concentration in water can be used to approximate the amount of heat being released from the Yellowstone volcanic system. By this criteria, Yellowstone Lake hosts the third largest thermal basin in the Park (the largest are the Upper and Lower Geyser Basins).

The hydrothermal fluids in Yellowstone's geyser basins and in Yellowstone Lake are mainly meteoric water (rain and snowfall) heated by deep circulation (several km/mi below ground) in hot rocky zones above the magma storage region. The fluids also include gases (like carbon dioxide and hydrogen sulfide) that are picked up from the magma. The ultimate chemistry of the fluids plays a major role in the variation we see in hot springs, geysers, mud pots, and fumaroles throughout the Park. For example, geysers usually form from very hot chloride-rich fluids, whereas mudpots form from steam vents where hydrogen sulfide reacts with oxygen to make sulfuric acid.

The effect of subsurface boiling as fluids rise to the Yellowstone Lake floor can be seen in chemical variations in hot springs. As hot fluids rise and pressure decreases, the steam separates from chloride-rich liquid. Steam may continue upward with the liquid, or it may find its own separate pathway to the surface.

Within Yellowstone Lake, hydrothermally active areas occur in the northern basin and in West Thumb, both of which are within the Yellowstone Caldera. Normal Yellowstone Lake water has a chloride content of 5.5 ppm (parts per million). Hot spring vents with lower chloride than 5.5 ppm represent steam vents, and hot springs with chloride higher than 5.5 ppm represent liquid-dominated vents. Variations in chloride at different vent areas show that some areas are steam dominated and others have a significant fraction of hydrothermal fluid.

Mapping of the composition of vents on the floor of Yellowstone Lake shows that different types of vents can be found together or separated. In the northern basin, most lake-bottom hot springs are dominated by steam, but chloride-rich fluids are found in the Mary Bay and Elliott's Crater hydrothermal explosion sites. In West Thumb basin, most fluids are chloride-rich, but steam-rich vents can be found in the shallower water around the basin's periphery.

Fully understanding how the hydrothermal systems function is a work in progress and has led, in part, to a large multidisciplinary project called Hydrothermal Dynamics of Yellowstone Lake (HD-YLAKE), funded largely by the National Science Foundation with additional support from the National Park Service and U.S. Geological Survey. HD-YLAKE is now in it third year of sampling and analysis, and exciting results will be coming out soon. Stay tuned!

(Map shows location of hot springs and chloride content of vent waters in the northern basin of Yellowstone Lake.)
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November 30th, 6:10 pm

USGS Volcanoes

Many seismometers that monitor U.S. volcanoes saw the #AlaskaEarthquake as the P and S seismic waves rang through the #Earth. BUT, large tectonic earthquakes rarely trigger volcanic eruptions; this is an active area of research, but there are only a few convincing cases globally, and those are most likely to occur at volcanoes already in eruption or primed to erupt.

Alaska Volcano Observatory published this statement:
• The current eruptive activity at Veniaminof, and the unrest at Cleveland, Semisopochnoi, and Great Sitkin, continues without change since this morning's large tectonic earthquake.
• AVO maintains ground-based networks for seismic and GPS monitoring of Alaska volcanoes, along with remote sensing methods such as satellite and infrasound.
• AVO’s volcano-monitoring networks also record tectonic earthquakes, and broaden the data set of all types of earthquakes, such as the tectonic earthquake experienced on the morning of 30 November 2018.
The M7.0 earthquake was tectonic and not volcanic:
• For more information about this tectonic earthquake, please visit the National Earthquake Information Center: earthquake.usgs.gov/earthquakes/eventpage/us1000hyfh/oaf/commentary and earthquake.usgs.gov/earthquakes/eventpage/us1000hyfh/executive or the Alaska Earthquake Center: earthquake.alaska.edu/anchorage-m70-what-we-know-so-far.
• The earthquake occurred at a depth of 24 miles beneath the surface (40 km).
• The earthquake occurred in the subduction zone - the interface between the Pacific and North America plates, which extends to depths of 24 to 37 miles (40 to 60 km).
• Subduction zones, where most active volcanoes are found, can generate high rates of earthquakes that are not volcanic.
• Aftershocks will occur.
• The Aleutian arc is a seismically active region, evidenced by the many moderate to large earthquakes occurring each year. Since 1900, this region has hosted twelve large earthquakes (M>7.5) including the May 7, 1986 M8.0 Andreanof Islands, The June 10, 1996 M7.9 Andreanof Islands, and the November 17, 2003 M7.8 Rat Islands earthquakes.
• The most recent large earthquake to occur in this area was the 2016 M7.1 Iniskin earthquake.

Links for further information:
USGS National Earthquake Information Center earthquake information: earthquake.usgs.gov/
Alaska Earthquake Center earthquake information: earthquake.alaska.edu/
NOAA tsunami information: www.tsunami.gov/
Earthquake preparedness information: www.muni.org/Departments/OEM/Prepared/Pages/EarthquakePrep.aspx
Alaska Volcano Observatory information statements and volcano status updates: avo.alaska.edu
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November 30th, 1:48 pm

USGS Volcanoes

All volcanoes in the Cascade Range of Washington and Oregon are at normal background levels of activity this week.
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Weekly Update: on.doi.gov/2hwAiRm

This webcam image shows a few lone visitors enjoying the snow at Mount Rainier National Park. The view is from Paradise, with Mount Rainier visible in the clouds. This webcam and others are available at www.nps.gov/mora/learn/photosmultimedia/webcams.htm.

#usgs #cvo #cascadesvolcanoobservatory #volcanoupdate
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November 30th, 12:30 pm

USGS Volcanoes

Alaska state seismologist Michael West from the Alaska Earthquake Center will go live on University of Alaska Fairbanks Facebook this afternoon, talking about this morning's earthquake near Anchorage.

University of Alaska Fairbanks
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November 30th, 4:37 am

USGS Volcanoes

It's #HVO #VolcanoWatch time! go.usa.gov/xPMWr

This is, without a doubt, the most intellectually exciting time to be a volcanologist at the USGS Hawaiian Volcano Observatory. The current inactivity at Kīlauea has so many possible outcomes that it is a real challenge to figure out what might happen next. And intellectual challenges are stimulating and exciting.

What will happen? New summit lava lake, resumption of eruption at Pu‘u ‘Ō‘ō, lava flows in Puna, further summit collapses, explosive eruptions from the summit, eventual collapse of the entire summit, renewal of caldera filling with lava eventually overtopping the caldera rim, decreased magma supply so that the quiet lingers for years, increased magma supply so that the quiet ends in months, resumption of Mauna Loa activity…or something else?

Any of those possibilities could happen, and we are challenged by having to weigh all of them and more. And this is hard. No matter how much we may know, the truism remains: there are no facts about the future.

One thing is clear. It is not the duration of the present quiet period that is so intriguing. There have been many other longer periods in the past 150 years with no lava visible, some lasting years. But those were times when monitoring was sparse and crude, ideas were rudimentary, and the scientific involvement was limited to a small number of generalists.

Now the monitoring capability is enormous and sophisticated, ideas about what might happen are varied and thoughtful, and the intellectual workforce spans the globe as local scientists receive input in near-real time from specialized, experienced, and insightful colleagues around the world. Much more can be made out of the current quiet than could be done before, and therein lies the challenge.

With all this firepower, can we get the outcome right, and if we can't—perhaps realistically the most likely outcome—then can we be within striking distance and learn enough to do better the next time? This is exciting stuff!

Research scientists need intellectual challenges. We are buffeted by daily personal and societal triumphs and failures, as are most people, while at the same time trying to find order in the chaos of the natural world that operates on a 24/7 schedule.

Creativity is the hallmark of research scientists, and it demands, almost paradoxically, an approach that is both focused on the problem at hand and broad enough to consider as many eventualities and ramifications as we can imagine.

Creativity is as important to research scientists as it is to artists. Both pursuits are limited by personal ability and the availability of tools of the trade. All artists and research scientists share the same need to come up with something new, to be different in ways that stimulate others to follow new directions or novel ways of thinking. The process of creating is exciting, no matter what the field, and it can lead to enjoyment and enlightenment for society when things fall into place.

There are differences, however. Creativity for a research scientist is bounded by physical and chemical realities, whereas the artist can pursue supernatural approaches. And, a research scientist strives to adhere to observations, facts, and logical inferences, whereas an artist is free to ignore such constraints.

The writer of this essay is nearing the end of a long eventful research career. It is no exaggeration to say that the current quiet at Kīlauea is the most exciting and challenging research time in 50-plus years of investigating the earth. Younger colleagues might think that's hyperbole, but with time they will realize the marvelous intellectual experience that the inactivity of Kīlauea provided them. Perhaps they will be lucky enough to experience something even more exciting before they hang up their boots. This writer hopes so but is doubtful.

Opportunities such as 2018 Kīlauea are unusual. When they happen, seize the day!

Photograph: This is a view of the summit area from the southwest, showing the collapsed area of Halema‘uma‘u and the adjacent caldera floor. A section of Crater Rim Drive preserved on a down-dropped block is visible at the far right. Volcanic gases rising from magma stored beneath the summit continue to escape to the surface, as they have for as long as Kīlauea has existed, resulting in deposits of sulfur on the crater walls. USGS Photo by Don Swanson.

#volcanoes #usgs #Kilauea #volcanology #research
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November 29th, 5:00 am

USGS Volcanoes

We know what ash looks like when it falls to the ground, but what does it look like up close?

Here is a backscattered electron image of ash erupted from Veniaminof volcano, Alaska, collected in the community of Perryville on October 26, 2018.

Most ash grains are composed of an andesitic matrix glass with abundant plagioclase, clinopyroxene and olivine microlites. These microlites are very small - about 25 microns in length (for comparison, human hair is about 75 microns in diameter).

All explosive volcanic eruptions generate tephra (fragmented rock) when magma or rock is explosively ejected. The smallest material is volcanic ash, which is less than 2 mm in diameter. Because of its size, ash is easily convected upward within a plume and can be carried downwind for very long distances. In this case, ash from Veniaminof traveled 22 miles south to the community of Perryville, where it was collected.

Looking at ash on such a small scale is very instructive. It provides basic information about what magma is made of, how long it hangs out and chills beneath the volcano, its pathway to the surface and how (or why) it blows itself apart. When it comes to understanding volcanoes, looking at things on a very small scale can help to develop the big picture.

Images taken on a JEOL 6510LV Scanning Electron Microscope. Annotation by Matt Loewen, Alaska Volcano Observatory.

Ashfall forecasts and instrument data for Veniaminof are available on the AVO webpage, at avo.alaska.edu/.

#usgs #avo #alaskavolcanoobservatory #veniaminof
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November 28th, 6:21 am

USGS Volcanoes

Check out this series of satellite images showing the progression of the Veniaminof eruption!

EOS
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November 27th, 11:13 am

USGS Volcanoes

The present-day science of volcanology rests upon shoulders of legendary field geologists. Our very own Don Swanson is one of them. A new GSA volume is dedicated to his contributions to the global understanding of volcanoes.

#volcanoes #usgs #fieldgeology #fieldvolcanology #volcanology
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November 26th, 8:10 am

USGS Volcanoes

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Monitoring systems show that activity at Cascade Range volcanoes remained at background levels throughout the past week.

volcanoes.usgs.gov/observatories/cvo/

Field crews were out during unseasonably mild weather last week to make upgrades to several monitoring stations at Mount St. Helens. The photograph shows three technicians installing a new enclosure and batteries at a permanent GPS site. Spirit Lake and Mount Rainier are visible in the background.

#volcanoes #mountsthelens #usgs #fieldwork #magmamonday
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November 26th, 7:51 am

USGS Volcanoes

Hawai'i Volcanoes National Park opened more of its trails over the weekend. ... See MoreSee Less

November 26th, 5:00 am

USGS Volcanoes

What would happen to the volcano if a nuclear blast occurred at Yellowstone?

#YVO has noted, with some amusement, tabloid headlines about various diabolical schemes to trigger an eruption of Yellowstone by nuking the caldera. If you find these crazy schemes somewhat unnerving, please don't be concerned--such a plan has zero chance of working! You see, unlike science fiction stories, in which nuclear weapons seem to be the cause of, and solution to, many geological catastrophes, science fact tells us that you aren't likely to trigger a Yellowstone cataclysm with a nuclear weapon. How do we know? It's because this experiment has already been tried!

Want to know more about this "experiment"? Check out this week's edition of #Yellowstone #CalderaChronicles!

volcanoes.usgs.gov/volcanoes/yellowstone/article_home.html

(Figure: Graph showing the average annual occurrence and equivalent energy release for earthquakes of different magnitudes.
Plot is from the Incorporated Research Institutions for Seismology (www.iris.edu/gallery3/general/posters/exploring_earth/EarthquakeFrequency).
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November 22nd, 6:00 am

USGS Volcanoes

We have a lot to be thankful about here at USGS Volcanoes.

This week, those of us in the Cascades were thankful for clear late-season fly days in order to improve monitoring equipment at Mount St. Helens.

Most importantly though, all of us at USGS Volcanoes are thankful for you and your continued interest as we take you on a journey of learning about U.S. volcanoes.

Happy Thanksgiving!

#USGS #volcanoes #HappyThanksgiving #givethanks #MountStHelens
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