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Reprinted from here.  Brought to you by Tour Guide and our new, comprehensive GPS/Internet/3G navigation App for iPhones and iPod Touch available today at iTunes!

View of Hualalai Volcano, Hawai`i, looking SE.  Photograph by J. Kauahikaua on December 30, 1996.
View of Hualalai Volcano, Hawai`i, looking SE.
Photograph by J. Kauahikaua on December 30, 1996.

The West Hawai`i Today issue for September 11, 2009, contained a letter to the editor titled “Hualalai is a real and present threat.” The writer’s main point was that “Hualalai is the ‘secret in the closet’ that nobody wants to talk about,” that Hualalai is under-monitored, and that, should Hualalai erupt, there is no evacuation plan.

The letter writer’s concerns about Hualalai were valid, but he was not aware of HVO’s current efforts and plans to improve the monitoring of Hualalai. We hope to shed some light on recent and future activities planned for Hualalai.

Hualalai is the third most active volcano on Hawai`i Island behind Kīlauea and Mauna Loa, according to the Hawaiian Volcano Observatory’s (HVO) Web site (http://hvo.wr.usgs.gov/), and attained national ranking of “High Threat” for active volcanoes in the U.S. (see http://pubs.usgs.gov/of/2005/1164/).

In the ranking, there were 37 volcanoes nation-wide that were highest-priority targets for improved monitoring; Kīlauea and Mauna Loa were included in this group. Furthermore, 21 additional volcanoes were found to be under-monitored and were regarded high priority for improved monitoring; Hualalai is in this group.

What is the basis for this ranking? Hualalai has erupted three times in the last 1,000 years, the most recent eruption occurring in 1801. An intense and damaging seismic swarm in 1929 marked a failed eruption. In the same interval, Mauna Loa and Kīlauea have each erupted more than 150 times, and Haleakala has erupted at least 10 times. Hualalai was rated a higher threat than Haleakala, due to the extent of development (airport, power station, etc.) and the larger population living on the volcano’s flanks.

Is Hualalai under-monitored? In 2005, HVO and the Pacific Tsunami Warning Center (PTWC) each had one seismometer on the volcano, and bi-annual deformation surveys were conducted by our staff. With the permission of Kamehameha Schools, a continuous GPS receiver was installed near the summit in late 2006. In 2009, HVO still has one seismometer and uses two instruments operated by PTWC for eruption monitoring, and we continue the bi-annual surveys. Plans for the next two years include upgrading our seismic site and adding a new one.

We routinely scrutinize all available satellite imagery daily, including visual and thermal images to indicate any significant visual and temperature changes, or increased gas emissions. Moreover, radar scans several times each year can pinpoint any ground deformation that may be a precursor to volcanic activity. The radar scans are so sensitive that several small areas of subsidence were detected after the October 15, 2006, Kiholo earthquakes.

The conclusion from evaluating all of these data is that there have been no signs of swelling, major subsidence, temperature changes, gas emissions, or unusual seismic activity on Hualalai that would indicate volcanic activity in the near future. Nevertheless, we continue to look for any changes.

If the rankings were done today, Hualalai would be nearly fully monitored.

We agree with the letter writer that “the more people know about Hualalai, the more will be prepared.” In 2004, University of Hawai`i at Manoa (UHM) scientists published two studies on Kona community’s perception of volcanic risk and preparedness for lava flows from Hualalai and Mauna Loa. They concluded that “current community understanding and preparedness… falls short of that required for a volcanic crisis, particularly for those eruptions with short onset and high effusion rates on steep slopes that would impact Kona in just a few hours…”

There are several reasons for the lack of understanding, but foremost may be the constant influx of new residents who haven’t educated themselves about volcanic hazards. The primary mission of the U.S. Geological Survey’s Hawaiian Volcano Observatory is to monitor the active volcanoes in the State of Hawai`i. Through our Web site, public forums, and newspaper articles, we strive to disseminate information on the volcanoes and their hazards.

The people of Kona should know that we are keeping an eye on Hualalai and that if there are any changes (in its eruption status), we will let the public know!

Kīlauea Activity Update

Lava continues to erupt from the TEB vent, on Kīlauea’s east rift zone and flow through tubes to the ocean at Waikupanaha. A deflation-inflation cycle this past week resulted in a reduction of lava supply for several days, followed by a resumption of flow on Wednesday, Sept. 30. Breakouts from the tube system started at that time, and these surface flows remain active at the top of Royal Gardens subdivision. The flows are mostly staying close to the breakout point along the east margin of the flow field.

Faint glow above the vent at Kīlauea’s summit has been visible at night. A portion of the Halema`uma`u vent cavity collapsed on Saturday, Sept. 26, followed by the appearance of an active lava pond deep within the vent cavity on the night of Tuesday, Sept. 29. Volcanic gas emissions remain elevated, resulting in high concentrations of sulfur dioxide downwind.

Four earthquakes beneath Hawai`i Island were reported felt this past week. A magnitude-2.3 earthquake occurred at 12:30 p.m., H.s.t., on Friday, September 25, 2009, beneath Kilauea’s summit at a depth of 6 km (4 miles). Two earthquakes occurred on Sunday, September 27-a magnitude-2.1 earthquake at 9:52 a.m., H.s.t., located 7 km (4.3 miles) N of Kailua at a depth of 8 km (5 miles) and a magnitude-2.3 earthquake at 10:22 p.m., H.s.t., located 7 km (4.3 miles) ENE of Honaunau at a depth of 6 km (3.7 miles). A 1.6-magnitude earthquake at 7:11 p.m. H.s.t., on Wednesday, September 30, was located 15 km (10 miles) NW of Mauna Kea’s summit at a depth of 25 km (16 miles).

Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov.

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Reprinted from: http://hvo.wr.usgs.gov/volcanowatch/2009/09_07_30.html

A Volcano’s Many Layers Determine the Richness of Hawai`i’s Groundwater Resources

Fresh water cascades from a spring on a cliff face into a pool next to the Pacific Ocean near Nahiku on the island of Maui. The water comes from rain that fell at higher elevations on Haleakala Volcano, seeped into the ground, and has traveled slowly toward the coast. (USGS photograph by Gordon Tribble from http://pubs.usgs.gov/circ/1312/c1312.pdf)
Fresh water cascades from a spring on a cliff face into a pool next to the Pacific Ocean near Nahiku on the island of Maui. The water comes from rain that fell at higher elevations on Haleakala Volcano, seeped into the ground, and has traveled slowly toward the coast. (USGS photograph by Gordon Tribble from http://pubs.usgs.gov/circ/1312/c1312.pdf)

Groundwater provides most of the fresh drinking water used in Hawai`i. Thus, discoveries that increase our understanding of the groundwater stored in our shield volcanoes are of great importance to us.

In matters of water, an island’s size counts, because the ability to wring moisture from passing air masses and hold it as groundwater depends on an island’s altitude and area above sea level. Also important is an island’s volcanic history, because it determines the rocks’ porosity (ability to absorb fluids) and permeability (“flow-through-ability”), which, in turn, affect the flow and storage of groundwater.

Having grown from the sea, a volcanic island is infused with seawater. Fresh water originates as rain, fog drip, or snow, some of which percolates into the lava flows to recharge groundwater. Most groundwater filters downward to sea level within the island, where it forms a freshwater lens-shaped body that floats upon denser salt water. The fresh-water lens thickens slightly inland, but, in most places, the top of the lens stands no more than a few meters above sea level.

The fresh-water lens is dynamic: groundwater flows constantly from inland areas of recharge to be discharged at the coast. Vertical dikes in rift zones tend to retard the lateral flow of groundwater and may impound (confine and store) it at high altitudes. Buried soil layers and ashy beds with low permeability impede the downward migration of water. They cause—above the fresh-water lens—the formation of small, perched aquifers, bodies of rock permeable enough to conduct groundwater. These dike-impounded and perched aquifers feed scattered springs found far above sea level on some islands.

Recent discoveries have added to this picture. In the 1990s, USGS hydrologists working in East Maui discovered that numerous perched aquifers in regions of abundant rainfall may be stacked until even the more permeable, intervening layers become saturated with groundwater. The result is a much thicker lens of fresh water, with an upper surface higher than the typical few meters of the conventional model.

At about the same time, researchers at the University of Hawai`i made a startling discovery about the role that soil and ash beds play in guarding the groundwater in the lava flows of Mauna Kea. Their findings resulted from chemical analyses of water in lava flows intercepted by drilling of the hole for the Hawai`i Scientific Drilling Project near Hilo Airport.

As the weight of the island bowed the underlying oceanic crust downward, these low-permeability soil and ash layers, now deep below sea level, prevented fresh and salt water from mixing. Thus, fresh groundwater fed by rainfall in lava-flow aquifers upslope persists well below sea level at the island’s edge. The layering of beds in the Hilo drill hole is like a sandwich of alternating fresh- and salt-water-bearing lava flows, each separated by low-permeability layers. Fresh water in the deep layers seeps unseen into the ocean at depths of 300 m (1,000 ft) or more.

Discoveries don’t end with Maui and Hawai`i, however. USGS hydrologists working in the Lihu`e basin of Kaua`i have found that low-permeability layers impounded a groundwater system that stands at least 100 m (300 ft) above sea level and more than that below sea level. The low-permeability layers were formed during late-stage volcanism, long after most of the island had been built. On Kaua`i, this volcanic stage, known as the rejuvenated stage, has produced rocks with characteristics that differ from those of more typical shield-building lava-flow aquifers. Natural seepage from the thick freshwater lens plays an important part in maintaining the flow of perennial streams in the basin.

The same low permeability that results in the formation of thicker freshwater lenses on Kaua`i and Maui and causes deeper fresh water to leak offshore from Hilo, however, also limits the rate at which groundwater can be extracted. Overpumping allows underlying brackish water to intrude and diminishes the flow to springs and streams. As with all natural resources, we need to manage our use of groundwater in a sustainable way. Recent and ongoing studies of Hawai`i’s geology and hydrology will enable us to do that more effectively.

Kīlauea Activity Update

Surface flows continued to be active on the pali in Royal Gardens subdivision. At the coast, the Waikupanaha ocean entry remains active, but the Kupapa`u ocean entry is no longer active. A deflation-inflation cycle (or DI event) started at the summit on Thursday, July 30 (the date of this writing). DI events often disrupt the lava supply to the east rift zone for several days.

The vent at Kīlauea’s summit was dark and quiet all week, producing only a very small quantity of rock dust from small collapses of the vent walls. Volcanic gas emissions have increased over the past two weeks and are currently similar to levels prior to June 30, resulting in high concentrations of sulfur dioxide downwind.

No earthquakes beneath Hawai`i Island were reported felt this past week.

Reprinted from here.

A laser’s look into the lua reveals how pit craters grow

Light detection and ranging (LiDAR) image of the southeast wall and currently active pit crater of Halema`uma`u.  Image courtesy of Todd Erickson, Pacific GPS Facility SOEST University of Hawaii, Manoa.
Light detection and ranging (LiDAR) image of the southeast wall and currently active pit crater of Halema`uma`u. Image courtesy of Todd Erickson, Pacific GPS Facility SOEST University of Hawaii, Manoa.

This month, researchers from the University of Hawai`i teamed up with the Hawaiian Volcano Observatory staff to use laser-based technology to peer into the depths of a new pit in Halema`uma`u. What they saw was startling. The look revealed that the vent has a cavernous interior that dwarfs the size of the opening that we see at the surface. The cavern is approximately 200 m (650 ft) below the floor of Halema`uma`u, making it a dizzying 285 m (935 ft) below the now-closed Halema`uma`u overlook area.

To obtain the image, the UH researchers were using a technology called Light Detection and Ranging, or LiDAR, for short. By bouncing pulses of lasers off objects, LiDAR can determine the distance to out-of-reach objects. Readers may be familiar with similar technology used in the laser range finders employed by golfers, hunters, and builders. Simple laser range finders measure a single distance to an object. In contrast, scientist using LiDAR data can produce entire images, or models, of distant surfaces based on thousands of individual laser bounces.

The remarkable part of the image is that it reveals a very deep pit crater with dramatic overhanging walls near the surface. This is different from the steep and vertical walls of the larger Halema`uma`u and Kilauea caldera.

What the image actually reveals is a snapshot in the evolution of a Hawaiian pit crater. “Pit crater” is a general term used to describe the steep-sided, semi-circular, and flat-bottomed craters that are characteristic of the summit and rift zone areas of Kilauea and Mauna Loa volcanoes. Interchangeable terms for these features include, “collapse crater”, and of course the eloquent Hawaiian name for a pit, “lua”. But how are these craters created?

Looking into this deep hole created by a volcano may lead one to think that all the material was blasted out. But if this were the case, we would be able to see a vast amount of excavated material deposited around the rim of the pit. In fact, the amount of ejected material, or ejecta, surrounding Hawaiian pit craters is relatively small — far less than the amount of material required to fill the hole back up. And, some Hawaiian pit craters do not have any ejecta surrounding them.

The answer to how pit craters form is being witnessed right now as the new vent evolves. Hawaiian pit craters form primarily through the evacuation, or loss, of magma somewhere beneath the vent. As magma evacuates from the plumbing system below, the conduits collapse and the vent floor sinks away. The walls may become overhung, since the interior of the pit expands as it drops. Eventually, the overhung portions of the rim collapse into the pit, and the characteristic near-vertical sides of the pit crater are formed.

Our observations of lava within the vent, data from instrumentation, and measurements of magma flux at the east rift zone near Kalapana, suggest that the amount of magma within the plumbing system of Kilauea has been reduced. This ebbing has caused the drop in the lava level and the growth of the cavern we now see. The recent pulses of ash-laden plumes issuing from Halema`uma`u have been caused by collapses of the pit’s overhanging rim.

Of course, the drop in the vent floor, and ebb in the flow of magma within the system, does not necessarily mean the eruption is winding down. A characteristic behavior of Hawaiian pit craters is that the floor may refill with a lava lake, only to drain and collapse again and again. So the laser’s look into the lua is certainly only a snapshot of the on-going evolution of Halema`uma`u.

Kīlauea Activity Update

Surface flows have been active on the pali within Royal Gardens subdivision throughout the past week, burning forest and one unoccupied structure. At the coast, the Waikupanaha and Kupapa`u ocean entries remain active and continue to produce steam plumes and small littoral explosions.

The vent at Kīlauea’s summit was dark and quiet all week, producing only a very small quantity of rock dust from small collapses of the vent walls. The plume has been thin and wispy, and volcanic gas emissions have been relatively low. They are, however, still elevated above background levels, resulting in high concentrations of sulfur dioxide downwind.

One earthquake beneath Hawai`i Island was reported felt this past week. A magnitude-2.8 earthquake occurred at 10:38 p.m., H.s.t. on Thursday, July 9, 2009, and was located 3 km (2 miles) south of Holualoa at a depth of 36 km (22 miles).

Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov.

For more information on visiting Hawaii in general and touring Hawaii Volcanoes National Park in particular, please also visit www.tourguidehawaii.blogspot.com and www.tourguidehawaii.com.

Reprinted from here.

2009—A year of noteworthy volcano anniversaries in Hawai`i

Thomas Jaggar (second from left) prepares to measure the temperature of the Halema`uma`u lava lake in 1917.  Pictured, left to right, Norton Twigg-Smith, Thomas Jaggar, Lorrin Thurston, Joe Monez, and Alex Lancaster.
Thomas Jaggar (second from left) prepares to measure the temperature of the Halema`uma`u lava lake in 1917. Pictured, left to right, Norton Twigg-Smith, Thomas Jaggar, Lorrin Thurston, Joe Monez, and Alex Lancaster.

Thomas A. Jaggar, founder of the Hawaiian Volcano Observatory (HVO), first visited Hawai`i 100 years ago during a decade-long period of exploration in which he witnessed first-hand the destructive power of volcanic processes.

His quest began in 1902, when Jaggar traveled to the West Indies just 13 days after two volcanoes there erupted with devastating consequences. The first eruption at La Soufriere on the island of Saint Vincent resulted in 1,500 deaths. It was followed only a few hours later by a second, more tragic, eruption at Mount Pelee on Martinique, in which 28,000 people perished. Jaggar’s experience at Martinique set the stage for his work on volcanoes and earthquakes during the next half century.

After Martinique, Jaggar’s expeditions took him to the scenes of earthquakes and volcanic eruptions in the Aleutians, Central America, and Japan. In 1908, an earthquake near Mount Etna in Italy killed 125,000 people. Following that natural disaster, Jaggar declared that “something must be done” to support systematic studies of volcanic and seismic activity.

The next year, in 1909, he traveled at his own expense to Hawai`i, where he determined that Kīlauea was to be the home of the first American volcano observatory. His vision was to “protect life and property on the basis of sound scientific achievement.”

In 1912, construction began on the new Hawaiian Volcano Observatory with support from Hawai`i businesses, private endowments through the Hawaiian Volcano Research Association, and funding from the Massachusetts Institute of Technology. HVO has since been managed by the U.S. Weather Bureau (1919-1924), U.S. Geological Survey (1924-1935), and National Park Service (1935-1947). The USGS became the permanent administrator of HVO in 1947.

In 2012, HVO will celebrate its centennial anniversary, a milestone made possible through the vision and efforts of Thomas A. Jaggar.

Today, in 2009, as we look back at Jaggar’s first visit to Kīlauea 100 years ago, we also reflect on the landmark anniversaries of several significant eruptions on Kīlauea and Mauna Loa:

25th1984 Mauna Loa summit and northeast rift zone eruption
40th — start of the 1969-74 Kīlauea east rift zone eruption (Mauna Ulu)
50th — 1959 Kīlauea summit eruption (Kīlauea Iki)
60th1949 Mauna Loa summit eruption
90th1919 Mauna Loa southwest rift zone eruption
150th1859 Mauna Loa northwest flank eruption

Reprinted from here.

A view of the lava lake within Halema`uma`u Crater on December 27, 1911, with Uwekahuna bluff (where HVO and the Jaggar Museum now stand) and Mauna Loa in the background. The lake level had risen about 120 m (400 ft) since October 1911 and will drop 90 m (300 ft) in January, 1912, the month that HVO was founded by Thomas A. Jaggar's arrival for duty.

A view of the lava lake within Halema`uma`u Crater on December 27, 1911, with Uwekahuna bluff (where HVO and the Jaggar Museum now stand) and Mauna Loa in the background. The lake level had risen about 120 m (400 ft) since October 1911 and will drop 90 m (300 ft) in January, 1912, the month that HVO was founded by Thomas A. Jaggar's arrival for duty.

The adage “a picture is worth a thousand words” is certainly true, especially when it comes to photographs of Hawaiian eruptions and volcanic landscapes from earlier times.

Long-time readers of “Volcano Watch” might recall our January 20, 2005, article (http://hvo.wr.usgs.gov/volcanowatch/2005/05_01_20.html), which describes an HVO geologist’s excitement at finding an 1860s photo of Kilauea’s caldera. By comparing the photo to a present-day view of the caldera, he could see the location of volcanic features described in written records (with less than a thousand words) but no longer visible today—a valuable discovery when your job is to decipher a volcano’s eruptive history.

Without realizing it, you or a family member may have captured a similarly important historical record of Hawai`i’s volcanoes. How? By taking a photo and keeping it.

Your `ohana, like many families, probably has several albums—or shoe boxes—filled with old photographs. Perhaps your great-grandmother took a picture of a long-ago Kilauea summit eruption or your brother snapped a photo of `a`a lava as it flowed down the slopes of Mauna Loa. If you possess photographs that show volcanic landscapes or features, volcanic fume (vog), or any kind of eruptive activity, HVO geologists would like to hear from you and see the photos.

We learn the most from photographs that have some documentation about when and where they were taken. Date and location are essential pieces of information that help us interpret the geologic significance of a photo. If people are recognizable in a photograph, their names should also be included. Any other details you can provide about the image will add to its meaning.

Wide-angle shots are more helpful than close-ups. For example, if a photo is zoomed in on the leading edge of a lava flow and shows nothing else, we cannot determine the size of the flow-or much of anything else—from the image. With wide-angle views, we can see the geographic or geologic context of the eruptive activity or volcanic features shown in the photograph.

If you’re interested in sharing your photos with HVO scientists, the first thing you should do is contact us by telephone (808-967-7328) or email us (askHVO@usgs.gov). Geologists are standing by to speak with you. The purpose of this initial conversation is to determine which of your photographs might be beneficial to our research and monitoring efforts on Hawai`i’s volcanoes. We will then send you additional information on how we can receive and duplicate photos selected from your collection.

No need to worry about giving up your photographs—you retain ownership of them. We will return your photos to you after duplicating the images selected as most useful. In appreciation of your loaning us the photographs, we will be happy to give you digital copies of the images we scan.

To kick off our effort to expand HVO’s photographic collection of Hawai`i’s volcanoes, we are asking at this time to see photographs from 1924 and earlier. Those years included frequent lava lake activity in Halema`uma`u Crater and culminated in the explosive eruptions of May 1924.

Pre-1924 photos are of particular interest to us now because they could shed light on Kilauea’s current summit eruption. Even if they show no eruptive activity, early photographs of Kilauea’s caldera can contribute to a better understanding of the volcano’s past and reveal features that are no longer visible. The same is true for early photos of Mauna Loa and Hualalai.

We will initially focus on early historical photographs, but you can contact us about any volcanic images you think might interest us. Although we may not be able to look at photos taken in recent decades right away, we would eventually like to see them. Our ultimate goal is to acquire images from the 1800s through the 20th century.

So, please lend us a hand while taking a trip down memory lane. Look through your family photos and contact HVO if you find images of Hawai`i’s volcanoes. Your old photographs could give new life to eruptive events and volcanic landscapes rapidly fading from our visual memories.

Kīlauea Activity Update

Surface flows in the Royal Gardens subdivision remained active as of Thursday, June 18, burning through forested kipuka. Another area of breakouts active higher up on the pali was also reported. The Waikupanaha and Kupapa`u ocean entries remain active and continue to produce prominent plumes as lava spills into the ocean.

At Kīlauea’s summit, the vent within Halema`uma`u Crater continues to emit elevated amounts of volcanic gas, resulting in high concentrations of sulfur dioxide downwind. Bright glow from the vent was visible at night through the past week. A collaborative effort last week between HVO and UH-Manoa scientists, using a sophisticated optical remote-sensing technology called LIDAR (Light Detection and Ranging), has measured the lava surface to be about 205 m (675 feet) below the floor of Halema`uma`u Crater.

No earthquakes beneath Hawai`i Island were reported felt this past week.

For more information on traveling to Hawaii in general and exploring the Big Island’s volcanoes in particular, please also visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.

Reprinted from here.

New Webcam menu makes lava views safely available

Lava in Kîlauea's summit vent creates a nighttime glow that can be safely observed from the Jaggar Museum overlook in Hawai'i Volcanoes National Park or on the HVO Webcam.  Inset image shows the lava surface, which was moving from top center to lower left at the time it was taken.
Lava in Kīlauea’s summit vent creates a nighttime glow that can be safely observed from the Jaggar Museum overlook in Hawai’i Volcanoes National Park or on the HVO Webcam. Inset image shows the lava surface, which was moving from top center to lower left at the time it was taken.

The HVO Web site was recently revamped to make access to our increasing number of Webcams easier for viewers and the HVO staff who post Webcam images. All HVO Webcams are now linked through a single menu at http://hvo.wr.usgs.gov/cams/.

The menu lists our five Webcams showing Moku`aweoweo, Mauna Loa summit caldera, the TEB vent and lava tube system on Kīlauea’s east rift zone, Pu`u `Ō `ō crater, and two views of the Halema`uma`u vent—one from HVO and another from the rim of Halema`uma`u crater immediately above the new vent.

Webcams allow us to make critical measurements with relatively little risk. The Webcams can work in rain, wind, very high concentrations of sulfur dioxide, and even moderate amounts of ash blasted from the vent. They can be in areas where access is restricted for safety reasons. Webcams can be where people should not.

Two of our Webcams have shown active lava in recent days. On Tuesday night, the TEB Webcam caught active flows near the top of the abandoned Royal Gardens subdivision. As an added treat, the Webcam also caught lights from a cruise ship passing the Kalapana shoreline in the late evening getting good views of the active flows and the Waikupanaha ocean entry.

The Webcams that chronicle developments below the floor of Halema`uma`u Crater have recorded lots of glow since early May. In fact, the recent glow has been the brightest since October 2008. The brightness of the glow is due to molten lava circulating in a narrow conduit about 100 m below the crater floor and about 180 m below the crater rim.

The Webcam located on the rim of Halema`uma`u was recently repositioned to look directly into the vent for views of the circulating lava when clear enough. The wispiness of the gas plume and the relative shallowness of the molten lava have allowed some good views recently. The vent is masked by sunlit fume during the day and is overexposed at night so the best times to look at Webcam views of lava are at dusk and dawn.

The unwavering Webcam views will allow us to better monitor the rise and fall of the lava within the vent. HVO geologists have also recorded video of the lava surface that shows some fascinating movements (http://hvo.wr.usgs.gov/kilauea/update/images.html). The lava emerges from the right side of the Webcam view and flows left across the opening. The flowing lava surface looks chaotic with lots of splashing and bursting bubbles—activity that produces the tephra that is carried aloft by the hot, rising gas and deposited on the rim.

Two recent Volcano Watches have discussed reasons for lava circulation using a lava lamp analogy. Magma must be convecting with the conduit, like the “goo” in a lava lamp, bringing hot, bubble-rich lava to the surface while allowing cooler, bubble-poor lava to sink.

Looking at lava within the Halema`uma`u vent conduit is like watching a lava lamp from above through a hole in the top, all the goo colored orange, and blobs being gas bubbles that burst when they get to the top.

Views from the Halema`uma`u Webcam should allow us to test our ideas about what precedes brown plumes and explosive eruptions. Do rocks fall from vent walls into the molten circulating lava trigger a vigorous gas release which could carry even more spatter and rock dust out of the vent. Or are the brown plumes and more energetic explosive eruptions initiated by a big slug of gas coming up the conduit.

For safety reasons, Hawai`i Volcanoes National Park restricts access to the entire caldera including Crater Rim Drive from Jaggar Museum south to the Chain of Craters Road intersection. Thanks to the HVO Webcams, we can all see what’s happening from much safer vantage points.

Kīlauea Activity Update

A deflation/inflation (DI) event at the summit of Kīlauea last weekend disrupted the supply of lava through the tube system and caused the Waikupanaha and Kupapa`u ocean entries to shut down. Both entries had resumed by mid-week, accompanied by breakouts near the top of Royal Gardens subdivision and just inland from Kupapa`u.

At Kīlauea’s summit, the vent within Halema`uma`u Crater continues to emit elevated amounts of sulfur dioxide gas, resulting in high concentrations of sulfur dioxide downwind. Vigorously upwelling lava within the vent below the crater floor produced bright glow at night, loud gas-rushing noises, and the emission of juvenile ash during the past week.

One earthquake beneath Hawai`i Island was reported felt this past week. A magnitude-3.4 earthquake occurred at 3:55 p.m., H.s.t, on Saturday, May 30, 2009, and was located 9 km (6 miles) southwest of Kīlauea Summit at a depth of 26 km (16 miles).

Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov. Volcano Watch is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.

For more information on traveling to Hawaii in general and touring the volcanoes of the Big Island in particular, please also visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.

Reprinted from here.

Magma within Kīlauea’s summit vent never goes flat

On May 14, a brief bit of clear weather shows the Halema`uma`u plume rising and blowing with the wind.
On May 14, a brief bit of clear weather shows the Halema`uma`u plume rising and blowing with the wind.

Two weeks ago, readers of this column learned about the genesis of brown plumes and sudden gas release from Kīlauea’s summit vent. This week we will continue that exploration, looking farther into Kīlauea’s magma plumbing system to explain why the summit vent has become a long-lived feature of the volcano.

As residents of the Big Island can attest, vog has been a substantial irritant since the formation of Kīlauea’s summit eruptive vent in early 2008. Can we expect this release of volcanic gas to go away anytime soon? The short answer is no, but that requires a bit of explanation.

As magma rises to shallow levels beneath the ground surface, pressure on the magma drops, and gas is released—similar to opening a can of soda (dropping pressure), allowing the dissolved carbon dioxide to bubble out. The magma will go flat once all of the gas is released, suggesting that Kīlauea’s summit should eventually stop releasing gas.

The persistence of volcanic gas emissions from Kīlauea’s summit is evidence that the supply of gas-rich magma is being replenished. To understand why, we’ll need to understand the principle of convection—in other words, how a lava lamp works.

In a lava lamp, heat added at the bottom warms the colored blobs within the lamp, causing them to become less dense and rise to the top. Since the top of the lamp is away from the heat source, the colored blobs gradually cool, become denser, and sink. The cycle repeats itself until the lamp is turned off.

A similar process is probably occurring beneath Kīlauea’s summit but is driven by gas release instead of by heat. Magma within the summit vent is like an open soda, where dissolved gases gradually come out of solution. As the magma goes flat, its density increases. Eventually, the dense, flat magma will sink and be replaced by less-dense, gas-rich magma—a lava lamp in action! As a result of this process, the summit plume of gas and ash is constantly renewed.

Besides the unusual persistence of the summit plume, there is other evidence that convection is occurring within Kīlauea’s shallow magma system.

If you read the Kīlauea daily activity updates, posted on the Hawaiian Volcano Observatory (HVO) Website each morning, or are a regular reader of this column, you’ve probably heard of “DI” events. “DI” is shorthand for “deflation-inflation.” These events occur as the summit suddenly begins to deflate and then, after about 12–48 hours, just as suddenly begins to inflate and returns to normal.

Prior to 2008, the average number of DI events occurring in any given year was about 10. In 2008, however, there were 47 DI events and, in 2009, there have already been 15 thus far.

DI events may be a physical manifestation of convection within Kīlauea’s shallow magma plumbing system. DI deflation could be caused by downward flow of dense, “flat” magma, with DI inflation representing the rise of fresh, gas-rich magma. During the time between DI events, fresh magma would gradually degas and become denser. The increase in the frequency of DI events in 2008 probably reflects the fact that, due to the start of the summit eruption, the magma rose to very shallow depths, allowing for much more efficient and rapid degassing.

Vent collapses, like the one that generated the spectacular brown plume in early May, are sometimes associated with DI events. Assuming that DI deflation signifies the downward flow of dense magma, collapses might be expected, due to removal of magmatic support from the eruptive vent.

Although magma convection is suspected at several volcanoes worldwide, the process is difficult to document, because there is no way to see directly into a magma chamber. At Kīlauea, however, the outstanding level of geophysical and geochemical monitoring has provides good evidence of convection just beneath the volcano’s surface.

Scientists at HVO will continue to study DI events, gas emissions, brown plumes, and other signals from the summit vent in hopes of learning more about Kīlauea’s magma plumbing system. There is no doubt that this lava lamp will be going for a long time to come, so stay tuned to this column and the daily activity updates for the latest information!

Kīlauea Activity Update

The Waikupanaha and Kupapa`u ocean entries remain active and are topped by robust laze plumes. Frequent small collapses have prevented either entry from building a large delta. There have been no lava breakouts from anywhere along the tube system reported in the last week.

At Kīlauea’s summit, the vent within Halema`uma`u Crater continues to emit elevated amounts of sulfur dioxide gas, resulting in high concentrations of sulfur dioxide downwind. Glow, gas-rushing noises, and the emission of juvenile ash during the past week suggest that a small lava lake is still present below the floor of Halema`uma`u Crater.

No earthquakes beneath Hawai`i Island were reported felt this past week.

Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov. Volcano Watch is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.

For more information about traveling to Hawaii in general and touring the Big Island in particular, please also visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.

Reprinted from here.

How do recent earthquakes fit into the Kilauea puzzle?

Hawaii earthquakes: USGS Illustration, reprinted from http://hvo.wr.usgs.gov/volcanowatch/2009/09_04_23.html.

Hawaii earthquakes: USGS Illustration, reprinted from http://hvo.wr.usgs.gov/volcanowatch/2009/09_04_23.html.

During the past two weeks, two noteworthy earthquakes struck Kīlauea Volcano’s south flank. While the south flank is among the most seismically active areas in the U. S., the vast majority of earthquakes beneath it are too small to be of general interest. At the same time, each earthquake beneath the volcano represents a piece of a very complex puzzle that we continually watch and study.

The earthquakes on April 14 (magnitude 5.0) and April 21 (magnitude 4.2) occurred at depths of roughly 9 km (5.5 miles) below the Earth’s surface in regions adjacent to Kīlauea’s east rift zone. These earthquakes gently punctuated the steady, southeastward motions of Kīlauea’s south flank. They are noteworthy because they were widely felt across Hawai`i Island (see http://earthquake.usgs.gov/eqcenter/dyfi/).

Parts of the active fault system responsible for the earthquakes are visible as the spectacular scarps that line Hawai`i’s southeast coast within Hawai`i Volcanoes National Park. A major part of the system—a fault representing the decollement, or detachment surface, between the ancient oceanic crust and the volcanic “pile” built up from repeated volcanic eruption and intrusion—becomes most apparent in larger earthquakes, as on April 14 or two of Hawai`i’s larger earthquakes in 1989 (magnitude 6.1) and 1975 (magnitude 7.2).

With capabilities afforded by continuous GPS monitoring, we measure considerable movement of Kīlauea’s south flank that occurs as steady or stable motion. Large in a geophysical context, the movements occur at rates of several inches (centimeters) per year. At a conceptual level, it is reasonable to view the decollement as a through-going and somewhat uniform fault beneath the flank.

The south flank fault system is more complex, however, when seen from the perspective of earthquake distributions. There are some regions of the south flank that are surprisingly devoid of earthquake activity. Looking back through the Hawaiian Volcano Observatory’s record of seismicity, patterns of south flank earthquake hypocenters, or computed locations, also display a general level of clustering.

While they are all related to the decollement, April 2009’s two earthquakes and the 1989 and 1975 earthquakes each occurred in distinctly separate south flank clusters. The magnitude-5.0 earthquake on April 14 occurred in one of the south flank’s western earthquake clusters. The magnitude-4.2 earthquake on April 21 occurred about 10 km (6 miles) to the east of that cluster. The 1989 earthquake was located a few kilometers (miles) east of the April 21 hypocenter, and the 1975 earthquake was about 8 km (5 miles) east of the 1989 hypocenter.

Interestingly, between the two clusters containing the April 2009 earthquakes lies a section of the south flank decollement system that has produced thousands of small earthquakes, but not a single magnitude 4 or larger earthquake since 1970. In comparison, during that same time interval, the April 14 magnitude-5.0 cluster has produced 30 such earthquakes, and the April 21 magnitude-4.2 cluster has produced 45 such earthquakes.

The earthquake clustering reflects variation in fault properties and fault structure along the decollement. Variation of earthquake behaviors within and among different clusters reflects additional complexity associated with movement of the south flank. In addition to understanding the fault properties and structures, we are striving to learn more about the forces resulting from magma residing in the rift zones and the frictional resistance along the active faults.

Each new south flank earthquake, especially if large enough to be felt, reprises questions of Kīlauea’s next possible magnitude-7 south flank earthquake. While we lack clear-cut answers to some of those questions, each earthquake compels us to look more closely and provides new information to fit into the Kīlauea puzzle.

Activity update

The Waikupanaha and Kupapa`u ocean entries remain active, with small littoral explosions common at the Kupapa`u entry over the past week. Surface flows inland from Kupapa`u remain active along the eastern boundary of Hawai`i Volcanoes National Park.

At Kīlauea’s summit, the vent within Halema`uma`u Crater continues to emit elevated amounts of sulfur dioxide gas, resulting in high concentrations of sulfur dioxide downwind. Variable glow and vent noises over the past week suggest that lava is still present at shallow levels below the floor of Halema`uma`u crater.

A magnitude-4.2 earthquake at 4:58 p.m. H.s.t. on Tuesday, April 21, was located beneath Kīlauea’s south flank, about 44 km (27 miles) south of Hilo and at a depth of 9.2 km (5.7 miles). The earthquake caused no significant changes to Kīlauea’s ongoing eruptions. More than 200 people reported feeling it (http://earthquake.usgs.gov/eqcenter/dyfi/events/hv/00033612/us/index.html).

Visit our Web site (http://hvo.wr.usgs.gov/volcanowatch/2009/09_04_23.html) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea summary; email questions to askHVO@usgs.gov.

For more information on traveling to Hawaii in general and touring the Big Island in particular, please also visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.

Reprinted from here.

Halema`uma`u March 24

Halema`uma`u March 24

A plume of volcanic gas and ash rises from a vent on the east side of Halema`uma`u Crater, at the summit of Kīlauea caldera. The Hawaiian Volcano Observatory and Jaggar Museum of Volcanology are in the foreground.

After one year, Kīlauea’s summit eruption is still going strong

(To see a recent video of Halema’uma’u eruption, go here)

It seems like only yesterday when the Hawaiian Volcano Observatory (HVO) monitored a several-week build-up in seismic tremor levels and sulfur dioxide emissions in early 2008. While some staff members speculated that a small summit eruption might be on the way, others were convinced, from the lack of earthquake activity and deformation, that Pele was just restless, and that a summit eruption was unlikely.

Then, on March 12, 2008, an area of gas emission formed on the east wall of Halema`uma`u Crater, within Kīlauea’s caldera. The extreme temperature of the gases caused the vent to glow at night, attracting tourists and locals alike to the viewpoint at the Jaggar Museum of Volcanology. Hawai`i Volcanoes National Park closed the south part of the caldera to visitors in response to the increased concentrations of hazardous gases—a closure which remains in effect today.

The real surprise occurred at 2:58 a.m. on March 19, 2008, when a small explosion occurred from the site of the gas emission. The explosion—the first at Kīlauea’s summit since 1924-threw rocks and boulders over about 40 hectares (100 acres), destroying the Halema`uma`u tourist overlook, blanketing the Halema`uma`u parking lot with rocks and ash, and marking the start of the summit eruption that continues to this day.

Since that event almost one year ago, thousands of tonnes of sulfur dioxide and other volcanic gases have issued from the March 19 explosion crater. The gas has had a tremendous impact on the residents of Hawai`i Island, damaging crops on the south part of the island and worsening existing health problems for people from Hilo to Kona.

Despite the widespread effects of the gas emissions, very little lava has erupted from the vent. A small amount of ash is produced every day, but the bulk of the lava that erupted has been the result of occasional explosions that occurred throughout 2008 (none have occurred in 2009-yet). Near-daily ash collection and mapping of explosive deposits reveal that the total amount of lava and ash erupted is too small to even fill your local supermarket! In fact, the amount of lava and ash produced by the summit eruption is equivalent to what is erupted from Kīlauea’s east rift zone in just five hours.

Even though only a small amount has actually erupted, lava has been seen within the vent. Visual observations identified a lava lake about 300 feet below the vent rim in September and October 2008. In February 2009, images from an infrared camera, which is able to see through much of the gas plume, saw a lava lake at a greater depth, about 450 feet below the rim. This lake has recently been replaced by a series of small, spattering vents, still well below the floor of Halema`uma`u Crater.

The current summit eruption has already surpassed the length of all previous summit eruptions at Kīlauea since 1924. In December 2008, HVO scientists thought that the eruption actually might be coming to a close, since activity diminished markedly. Instead of dense, white, roiling, emissions, the plume was wispy, thin, and lazy. Glow disappeared from the vent, and seismic tremor levels dropped considerably.

Of course, Pele was just being her usual, devious self. In January, the return of weak glow and a strong, white plume signaled the renewal of the summit eruption. One year in, there are no signs that the eruption will be ending anytime soon.

The past year has been one of surprises, to say the least. The type of activity currently on display at Kīlauea’s summit is unprecedented in the nearly 200 years of recorded eruptions. HVO will continue to closely monitor the eruption to improve our knowledge of how Kīlauea works and to watch for signs of clearing air that might signify the end of this chapter of Kīlauea’s history.

Activity update

The Waikupanaha ocean entry remains active, and a small collapse early Wednesday morning (3/11) removed part of the delta there. West of the ocean entry, lava flows were active on the coastal plain and had reached to within 180 m (200 yds) of the ocean near Kupapa`u by mid-morning on Wednesday.

At Kīlauea’s summit, the vent within Halema`uma`u Crater continues to emit elevated amounts of sulfur dioxide gas, resulting in high concentrations of sulfur dioxide downwind. Lava remains just out of sight more than 90 m (100 yds) below the vent rim.

Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea summary; email questions to askHVO@usgs.gov. skip past bottom navigational bar

For more information on traveling to Hawai in general and seeing the volcanoes of the Big Island in particular, please visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.

Photo by Donnie MacGowan

Halema'uma'u's Eruption Plume Glows in the Night Like the Door to Hades Was Left Ajar: Photo by Donnie MacGowan

Reprinted from here.

It seems that something new and different is always cooking at Kīlauea. In December a change in the aroma coming from Pele’s kitchen was noticed by the HVO and National Park staffs, along with nearby residents. The biting, choking odor of sulfur dioxide (SO2) from Halema`uma`u that had inundated Volcano Village and the Golf Course subdivision during trade wind disruptions started to change. The pervasive odor of rotten eggs or sewer gas that tainted the air was caused by an increasing appearance of hydrogen sulfide (H2S.)

The presence of H2S at Kīlauea’s summit is not unusual in itself. Visitors to Sulphur Bank, located near Kīlauea Visitor Center, have long experienced the characteristic mix of odors. As Mark Twain quipped during his 1866 visit to Kīlauea, “The smell of sulphur is strong, but not unpleasant to a sinner.”

Twainian humor aside, H2S gas, like SO2, can be hazardous at concentrations greater than 5-10 parts per million (ppm). Eye irritation and headaches are frequently reported symptoms. The human nose—very sensitive to H2S when first smelled—is able to detect it at concentrations well below 1 part per million. Unlike SO2, however, olfactory fatigue causes a loss of odor sensitivity upon prolonged exposure. The State of Hawai`i hosts a 1-hour ambient air standard for H2S of 0.025 ppm. California enacted a similarly protective standard in 1969, targeted at decreasing odor annoyance. The World Health Organization established a 24-hour average guideline of 0.15 ppm intended to protect human health.

H2S is formed at Sulphur Bank when SO2 escaping from Kīlauea’s magma chamber rises and combines with ground water. The resulting chemical reaction, called hydrolysis, produces a mixture of SO2 and H2S at the surface. The amount of gas released is very small, and when the emissions are blown toward Halema`uma`u, they tend to affect only a small section of Crater Rim Drive.

Apart from the background Sulphur Bank gas emissions, HVO scientists have been watching carefully for appreciable H2S coming from the Overlook Vent at Halema`uma`u since the eruption began last March. A substantial increase in this gas, along with other eruptive indicators, might signal that a large amount of water was coming into close proximity of red-hot magma. The subsurface encounter of abundant groundwater and magma was the suspected culprit causing the explosive eruptions of 1924.

The lack of significant H2S presence at Halema`uma`u through late November reflected hot, dry conditions within the vent. And SO2 emissions remained high, as well, despite significant collapses of the vent rim and walls in September and October that added large amounts of rubble to the conduit bringing gas and other eruptive products to the surface.

This situation began to change in early December, when further collapses widened the vent rim to football playing-field size-100 m (110 yards) Accompanying the vent-widening was some seasonally notable rainfall. The gage at HVO recorded over a foot of rain in December, much of it during a single storm late in the month.

Hot, collapsed rim and wall rock accumulating in the vent, combined with the prodigious rainfall, provided good conditions to produce H2S from SO2 within the conduit. By mid-December, the vent had cooled somewhat, and the ratio of H2S to SO2 in the air near Halema`uma`u had climbed to higher levels than seen previously.

Despite the seemingly favorable H2S-producing conditions, the total emissions, while significant, were still less than one tenth those of SO2. HVO staff, however, watched the situation unfold with great interest, wondering what might happen next.

Pele’s SO2 exhalations were not to be dampened by a little rainfall, though. By mid-January, the rains had tapered off, and magma heat and gas from below the rubble in the vent appeared to burn through. By late January, faint glow was once again seen in the vent, and the presence of H2S declined to near background as the vent heated up and dried out. And so, for now, it seems that hot liquid rock is once again what’s cooking at Kīlauea’s summit kitchen. Ah, pungent sinner soup! Can you smell it? Can you taste it?

Activity update

Kīlauea Volcano continues to be active. A vent in Halema`uma`u Crater is emitting elevated amounts of sulfur dioxide gas and producing very small amounts of ash. Resulting high concentrations of sulfur dioxide in downwind air have closed the south part of Kīlauea caldera and produced occasional air quality alerts in more distant areas, such as Pahala and communities adjacent to Hawai`i Volcanoes National Park, during kona wind periods. Variation in glow, gas-rushing sounds, and ash production over the past week may indicate that conduit beneath the vent is periodically being closed with debris.

Pu`u `Ō`ō continues to produce sulfur dioxide at even higher rates than the vent in Halema`uma`u Crater. Trade winds tend to pool these emissions along the West Hawai`i coast, while Kona winds blow these emissions into communities to the north, such as Mountain View, Volcano, and Hilo.

Lava erupting from the Thanksgiving Eve Breakout (TEB) vent at the eastern base of Pu`u `Ō`ō continues to flow to the ocean at Waikupanaha through a well-established lava tube. Breakouts from a western branch of the lava tube were active on the coastal plain near the National Park boundary in the past week and reached the ocean again on January 28. This tiny, new ocean entry is located very close to the long-buried Waha`ula Heiau and National Park visitor center.

Be aware that active lava deltas can collapse at any time, potentially generating large explosions. This may be especially true during times of rapidly changing lava supply conditions. The Waikupanaha delta has collapsed many times over the last several months, with three of the collapses resulting in rock blasts that tossed television-sized rocks up onto the sea-cliff and threw fist-sized rocks more than 200 yards inland.

Do not approach the ocean entry or venture onto the lava deltas. Even the intervening beaches are susceptible to large waves generated during delta collapse; avoid these beaches. In addition, steam plumes rising from ocean entries are highly acidic and laced with glass particles. Call Hawai`i County Civil Defense at 961-8093 for viewing hours.

Mauna Loa is not erupting. Four earthquakes were located beneath the summit this past week. Continuing extension between locations spanning the summit indicates slow inflation of the volcano, combined with slow eastward slippage of its east flank.

One earthquake beneath Hawai`i Island was reported felt within the past week. A magnitude-2.3 earthquake occurred at 1:20 a.m., H.s.t., on Tuesday, January 27, 2009, and was located 9 km (6 miles) northwest of Kukuihaele at a depth of 42 km (26 miles).

Visit our Web site (http://hvo.wr.usgs.gov) for daily Kīlauea eruption updates, a summary of volcanic events over the past year, and nearly real-time Hawai`i earthquake information. Kīlauea daily update summaries are also available by phone at (808) 967-8862. Questions can be emailed to askHVO@usgs.gov.

For more information on traveling to Hawaii in generally and seeing the volcanoes on the Big Island in particular, please visit www.tourguidehawaii.com and www.tourguidehawaii.blogspot.com.