Category: Alaska and Aleutian

Donna Shillington (Lamont-Doherty Earth Observatory at Columbia University)

Figure 1. Simplified map of the Alaska Subduction Zone, showing distribution of catalog (white dots) and notable (yellow stars) earthquakes along the margin. Red arrows indicate absolute plate motions

The Mission: Mapping the Alaska Megathrust

The 2500-km-long subduction zone offshore southern Alaska regularly produces large, destructive earthquakes. One of the big conundrums about these settings is how large of an area locks up on the contact between these plates (called the ‘megathrust’) and then ruptures in earthquakes. To tackle this question, my colleagues and I collected data on land and at sea in the summer of 2011 to produce an image of the megathrust, constrain the properties of rocks around and within the megathrust and link these fault properties to the earthquake history here. Our expedition focused on a part of the subduction zone off the Alaska Peninsula that exhibits very big changes in slip behavior. Some parts of this plate boundary lock up and then rupture catastrophically in big earthquakes. In other areas, the plates appear to be smoothly sliding by each other and thus do not produce great earthquakes. The Semidi segment last ruptured in a great earthquake (magnitude 8.3) 73 years ago in 1938. This area has an estimated recurrence interval of ~50-75 years, and thus might be due to produce another big earthquake soon. However, just to the west lies the Shumagin gap, an area that has not produced a great earthquake historically. Imaging a major fault boundary that lies tens of miles under the seafloor is not an easy task, but we had exceptional tools for the job. We used the R/V Marcus G. Langseth to acquire seismic reflection data and onshore/offshore wide-angle reflection/refraction data. Sound waves generated by an array of air guns were recorded on two 8-km-long streamers, an array of ocean bottom seismometers and onshore seismometers.

Figure 2. Katie Keranen and Guy Tytgat deploying a seismometer in Port Heiden

June 17-24: Installing seismic stations on the Alaska Peninsula

The first component of our program involved deploying seismometers onshore around the Alaska Peninsula with Katie Keranen (Univ. OK) and Guy Tytgat (PASSCAL). These instruments recorded small, local earthquakes, distant large earthquakes and (importantly for our project) the sound source of the R/V Langseth. The Alaska Peninsula is too rugged and expansive for a network of roads, so planes, helicopters or boats are the only transportation options. We decided to charter a plane based in Nelson Lagoon, a town of 80 people situated on a long, narrow sandy spit jutting out into the Bering Sea. The weather dictates when and where you can fly each day, and it varies dramatically. We were lucky enough to have several clear days (even saw some blue skies and sunshine!), but other days we were grounded by weather and wiled away the time indoors at our inn. While we were in the air, we saw majestic, snow capped volcanoes shrouded in clouds, expansive views of the sparsely vegetated Alaska Peninsula, which is riddled with rivers and lakes, and lots of wild life: caribou, bears, seals, walruses and eagles (just to name a few). It is a landscape that seems remarkably untouched by humanity.

Local communities were unwaveringly helpful and friendly in helping us find places for our stations. The two school districts here kindly granted us permission to install our seismic stations at any of their schools, and we also obtained permission to place equipment at various lodges and village offices. Residents volunteered to take our gear and us from the airstrip to our sites. In one town, our pilot made a general plea over the radio: “Is anyone listening on Channel 3? I’m here at the airstrip with scientists who need a ride to the school”. Someone answered immediately and picked us up 5 minutes later.

Many of our sites are in spectacular places near remote lodges or in towns nestled between mountains and the ocean. All of them are home to impressive wild life that poses a risk to our equipment, particularly bears. We protected the equipment against curious small animals but fully bear-proofing a station for a short (two-month-long) deployment was not feasible. Instead, we hoped that placing our stations in villages (rather than in the wild) would provide some protection, but we also needed good luck…

Figure 3. The R/V Langseth in port of Kodiak, with snowy mountains in the background

June 24-29: Transitioning from land to sea

Seven days and eleven flights after we arrived in Alaska, we finished deploying our seismic stations onshore. Our final constellation of stations differed a little from our original plan (as they always do), but achieved our main goal of instrumenting the part of the Alaska Peninsula nearest to our planned offshore work on the R/V Langseth. As luck would have it, we finished deploying our seismometers just in time to catch a large earthquake (magnitude 7.4) that occurred farther west in the Aleutians around the Fox Islands. After the onshore work was finished, Katie and Guy departed for home, and I flew to Kodiak to meet the R/V Langseth and our shipboard science party, including other chief scientists Mladen Nedimović (Dalhousie) and Spahr Webb (LDEO). Kodiak offered beautiful sights, delicious seafood and local beer (including Sarah Pale Ale!), but our science party was eager to leave for sea. We departed Kodiak on a sunny evening on June 29 for our 38-day-long research cruise.

June 29-July 11: Deploying and retrieving ocean bottom seismometers

The next part of our program involved using ocean bottom seismometers (OBS) to record seismic waves generated by the sound source of the Langseth. OBS’s are autonomous instruments that sit on the seafloor and record sounds waves traveling through the earth and the water. Floats made from glass balls and syntactic foam make each OBS buoyant, but an anchor holds it on the seafloor during the study. We placed OBS’s from Scripps Institution of Oceanography on the seafloor along two lines extending across the major offshore fault zone. The larger the distance between the sound source (earthquakes or air guns) and the seismometer, the deeper into the earth the recorded sound waves travel. OBS are not attached to the vessel and are also very sensitive, so they can record sound waves generated very far away (commonly >200 km). Because we want to examine deep fault zones that cause large earthquakes off Alaska, OBS are a critical part of our effort.

To deploy the OBS, we simply lifted them over the side of the ship with a large crane and gently dropped them in the water, after which they slowly sank to the seafloor. It never ceases to amaze me that we can throw a bundle of very sophisticated electronics over the side of the ship and hope to pick it up and retrieve information from it. Yet, it works! After leaving OBS on the seafloor along each line for ~3 days to record sound waves generated by the air guns of the Langseth, we returned to collect them. After receiving an acoustic signal to release from its anchor, the OBS rises through the water at 45 meters per minute. When the water is deep, it can be a long wait. Some of ours were 5500 m below the surface! The recovery of OBS always involves a certain amount of suspense. Despite all of the advanced engineering and planning that goes into these instruments, it is an inherently risky endeavor. Happily, we recovered 100% of our OBS.

Figure 4. Deploying an OBS

Despite all the technology required to place a seismometer many miles below the ocean on the seafloor and summon it back to the surface, many aspects of actually plucking the OBS out of the ocean and pulling it on deck are remarkably low tech. Once the OBS is spotted floating on the surface, the ship drives along side. It is akin to driving your car up next to a ping-pong ball. Scientists and techs lean over the starboard side of the Langseth with large poles and attempt to attach a hook with rope to the top of the OBS. Its not always easy since the OBS is bobbing up and down on the waves. Once we hook it, we can attach a rope to the wench and haul the OBS onboard. Sometimes, OBS bring back surprises – an octopus returned with one of our OBS! He was alive and healthy, so we returned him to the ocean (though some lobbied that we keep him for lunch…)

July 11-August 5: Seismic reflection profiling with miles and miles of streamer

On July 11, we finished our OBS work, and began the second phase of the cruise: recording sound waves from the Langseth’s airgun array with two 8-km-long (5-mile-long) cables (or streamers) filled with pressure sensors. Changing gears in terms of scientific activities also involved changes to our science party; we swapped personnel by boat transfer in Sand Point on a beautiful sunny evening. The Scripps OBS team departed, and we were joined by new reinforcements, including five undergraduate students from Columbia University.

Our seismic streamers are stored on gigantic spools, which unreel cable off the back of the ship into the ocean. A large buoy is affixed to the end of the streamer, and ‘birds’ are attached along its length, which can be used to control the depth of the streamer. Large paravanes hold the streamers apart; these are like large kites flying off the back of the ship in the water. Deploying miles of streamer and the other attending gear is an impressively long and complicated undertaking, which also involves a fair amount of intense manual labor. But after 3 days, all of the gear was in the water. Once data acquisition began, we settled into a routine of watchstanding and standard shipboard data processing. Ship time is precious, so we collect data 24 hours a day, seven days a week.
One of the core objectives of our project is to image the deep parts of the plate tectonic boundary, which required us to go as far north (and as close to the coast) as possible. This was easier said that done! The southern edge of the Alaska Peninsula is rugged and flanked lots of small jagged islands and shallow features just below the surface of the ocean, and there is also more fishing activity close to the coast; both pose risks to the seismic gear. One of our closest approaches to land was near Unga, one of the Shumagin islands. At the apex of the turn, our streamers came within less than a mile of the coast. Due to some early difficulties with our equipment, we had to repeat this maneuver several times. I held my breath and watched our third (and final) pass from the bridge. After the ship and gear passed safely through the most harrowing part of the turn, the captain turned to me and asked, “We’re not going to do this again, are we?” Thankfully not! At least not there. But there were several other important parts of our survey that required close approaches to the coast to image critical parts of the boundary.

Figure 5. Watch-standers at work in the lab

Over the course of our cruise, we were treated to amazing views of marine life, including fish, whales, seals and birds. On one memorable day, we found ourselves surrounded by three species of whales, including a rare North Pacific Right Whale. But we tried to keep our distance from marine mammals. Since we are creating sound waves to image the earth, and they use sound to navigate and communicate with one another, our activities might disturb them; we suspended operations if a mammal came too close.

We used our new data to create very preliminary images of the structures below the seafloor as we went. A regular sight in the main lab was a group of people gathered around a computer screen or a large paper plot, talking and pointing excitedly. It was exhilarating to glimpse faults, sediments and other structures in our data for the first time and ponder what they might be telling us about this active plate tectonic boundary. But we have a lot of hard work ahead after the cruise to obtain concrete results from our voluminous data – we acquired over 3 Tb (3000 gigabytes!) of raw seismic data during the cruise! At 6:30 am on August 5, the R/V Langseth pulled into port in Dutch Harbor, marking the end of our very successful research cruise. Our steam into port from our study area involved a trip through Unimak pass and beautiful views of Aleutian volcanoes, including majestic Shishaldin.

Figure 7. Bears at Bear Lake, Alaska

August 5-10: Back to the Alaska Peninsula

Many people flew home after our arrival in Dutch Harbor, but not me! (At least not immediately). Katie Keranen and I returned to the rugged Alaska peninsula to recover the land seismometers that we deployed way back at the beginning of the summer. An Anchorage-bound flight from Dutch Harbor dropped me off in Cold Bay to rendezvous with Katie. After the plane landed, the stewardess asked for our “Cold Bay passenger” to disembark. Passenger. Singular. I filed past all the folks heading to Anchorage and beyond. Katie and I returned to all of our sites by charter plane. According to our pilot, it was a very foggy summer on the Alaska Peninsula, but we were blessed with excellent weather, allowing us to pick up all of our instruments in just a day and a half. Multiple attempts were required to recover a seismometers we placed Heredeen Bay; on the first try, we saw a large brown bear only 20 feet away from the plane! But to our delight, none of the stations had been disturbed by wild life, and all of them recorded data for the entire summer. After recovering our last station at Bear Lake, we rewarded ourselves by lingering at beautiful lodge there. We tried (unsuccessfully) to catch some fish and watched bears pick through the brush on the other side of the river. And after an amazing 55 days on and around the spectacular Alaska Peninsula, I happily headed back to NYC.

Special thanks to the following:

Onshore Science Party: Katie Keranen (Univ. Oklahoma), Donna Shillington (LDEO), Guy Tytgat (Passcal Instrument Center)

Offshore Science Party: Donna Shillington (LDEO), Mladen Nedimovic’ (Dalhousie University), Spahr Webb (Lamont), along with Ann Bécel, Matthias Deleschluse, Harold Kuehn, Jiyao Li, Berta Biescas, Aaron Farkas, Andrew Wessbecher, Celia Eddy, Kelly Hostetler, Hannah Perls, Jack Zietman

Figure 6. Donna and Katie on their way to another station.

“Report from the Field” was designed to inform the community of real-time, exciting GeoPRISMS -related research. Through this report, the authors expose the excitement, trials, and opportunities to conduct fieldwork, as well as the challenges they may have experienced by deploying research activities in unique geological settings. If you would like to contribute to this series and share your experience on the field, please contact the GeoPRISMS Office at info@geoprisms.nineplanetsllc.com. This opportunity is open to anyone engaged in GeoPRISMS research, from senior researchers to undergraduate students.
We hope to hear from you!

AGU Fall Meeting 2013, San Francisco, USA

¹LDEO; ²University of Alaska, Fairbanks; ³USGS; ⁴University of Wyoming; ⁵University of Wisconsin; ⁶University of South Carolina

Modified from: B. Jicha, G. Yogodzinski and P.B. Kelemen, Sharing Resources for Aleutian Arc Research, Eos, 2014

The Aleutian Arc (Photo Google Earth)

Aleutian-MW-AGU2013A Mini-Workshop, with support from GeoPRISMS, was organized to explore options for shared logistical support for NSF funded research in the Aleutian volcanic arc, which is part of the GeoPRISMS Alaska Focus Area. The goal is to reduce the logistical costs per project in order to enable a larger group of investigators to benefit from the opportunity that the GeoPRISMS focus is intended to foster. The workshop was held in the Fillmore ABC meeting rooms, in the Grand Hyatt San Francisco Hotel on Sunday, December 8, 2013 from 12:40 to 6:00 PM.

Despite inclement weather across North America, which prevented some registrants from attending, there were more than 90 participants from more than 60 universities and research organizations, mostly in the US.

The workshop began with a series of very short “Keynote” talks – mostly 10 minutes long, with speakers limited to 3 to 5 Powerpoint/Keynote slides, linking fundamental science problems with likely needs for logistical support in the Aleutians. These presentations were summarized by John Powers, who then outlined some end-member options for shared logistical resources.

Following the scheduled talks, there was a period for plenary discussion during which participants could present a single slide or simply comment from the floor. Including a couple of short coffee breaks, this plenary discussion occupied about three hours of the meeting. Results are summarized below.

Science

The Aleutian arc, where the Pacific Plate subducts beneath the North American Plate, is arguably the best place on Earth to investigate several fundamental questions about arc magmatism and the conditions that create new subduction zones. It has never been rifted, so that the entire crust formed by arc processes can be geophysically imaged. Subduction erosion has exposed older sections of arc crust in the fore-arc, allowing geochronology of the entire edifice. The oceanic arc has abundant, exposed mid-crustal intrusions, providing insight into the composition of plutonic arc crust, which is almost unique among intra-oceanic volcanic arcs. The major and trace element contents of the volcanic rocks are more similar to continental crust than any other intra-oceanic arc, whereas the Sr, Nd, Hf and Pb isotopes in the western part of the arc are the most depleted of any arc, worldwide, recording a depleted mantle source with essentially no input from a terrigenous sediment component. Thus, the Aleutians represents the best place on Earth to study formation of “juvenile” arc crust, similar to continental crust, with little or no incorporation of older, inherited continental material. Pilot studies have demonstrated strong links between volatile contents, major element composition, and trace element abundance in lavas, with profound implications for magma generation and differentiation processes. The Aleutians have been the site of great earthquakes, among the largest ever recorded, and of large volume submarine landslides. They sit astride major air transportation routes, rendering the volcanic hazard particularly acute. Subduction rates, and the depth of sediments in the trench, decrease systematically from East to West, offering the opportunity to study the effect of these factors on arc magmatism and deformation.

Several participants gave brief presentations on existing Aleutian data and potential sites for future exploration in geochemistry, active and passive source seismology, geochronology, tectonics, and deformation. All provided insight on the logistical requirements for such research.

All participants were invited to submit latitudes and longitudes of sites where they wish to do geological field work or make geophysical observations.

Logistics

Following science-based presentations, additional speakers described the benefits of using a shared facility for fieldwork as well as the operations of the Alaska Volcano Observatory, Earthscope, the Plate Boundary Observatory, and the German-Russian KALMAR project, which has been and will continue to be active in the westernmost Aleutian and Bering Sea regions.

Field campaigns in the Aleutians are logistically challenging and expensive unless research is conducted in the vicinity of one of the few airports, which are widely spaced along the more than 2,500 kilometers of plate boundary. Further, an amphibious approach is required for collecting geological, geophysical, and geodetic data from the numerous active volcanoes.

In the plenary sessions, attendees discussed several logistical matters: Should such a facility be used primarily for research in the oceanic Aleutian arc, or extended to include field campaigns on the Alaska Peninsula? Is there a need for shared ship support that may not require a helicopter (i.e. M/V Tiglax)? Could cost-effective research be conducted with a vessel capable of supporting helicopter operations. If so, would a small (80-120 foot) ship be sufficient, or is a larger UNOLS vessel with a helicopter required? Would it be possible to achieve most science goals with a helicopter based from commercial airstrips (in the oceanic arc away from the continental shelf, these are on Unalaska, Atka and Adak Islands, and perhaps also Attu) plus a small vessel without a helicopter?

Participants also discussed how to best share existing samples and data so as not to duplicate prior field campaigns. Workshop attendees determined that a logistics manager or office may be needed to coordinate efforts once a field facility is in place.

A key workshop outcome was a strong consensus in favor of developing shared field platforms that include a ship and helicopter. This could be in the form of a ship with a helipad, or perhaps a combination of a smaller ship and chartered helicopters based at airstrips with commercially available fuel (in the oceanic arc these are on the Unalaska, Atka and Adak Islands). When asked whether, if such support were available, participants would write proposals to NSF to take advantage of this support, 28 people present (of perhaps 50 or 60 at that point) raised their hands. At the same time, conveners asked for dissenting votes, and there were none. This highlights the potential for having about 20 proposals submitted to GeoPRISMS to make use of such shared logistical resources.

Participants in both the seismic and geodetic communities stressed that the ship/helicopter platform(s) would need to be available for a minimum of two and ideally three summers so that instruments can be deployed, collect a sufficient amount of data, and be retrieved. The distance range of helicopters based at airstrips would be insufficient to achieve optimal, uniform instrument distribution over significant distances along the arc. Bringing instruments onshore from ships using small boats would be unreliable, is dangerous, and would result in less-than-optimal instrument sites. Thus, the workshop participants who are planning onland deployment of seismic and geodetic instruments strongly favor a ship-based helicopter platform. In turn, most workshop participants favor a combined geophysical, petrological and geochemical approach for GeoPRISMS-supported work in the Aleutians, and thus there is a consensus that the ship-based helicopter platform is best for the community, though this consensus is not as strong as the overall support for shared resources in general.

Go to the Mini-Workshop webpage

GeoPRISMS Newsletter, Issue No. 32, Spring 2014. Retrieved from http://geoprisms.nineplanetsllc.com

Taryn Lopez, GeoPRISMS Posdoctoral Fellow (University of Alaska Fairbanks)

Fluid movement in the subsurface of active volcanoes is frequently thought to produce abundant seismicity, but the actual type of fluid, including magma, volcanic gases, or hydrothermal waters, cannot yet be constrained from seismic data. Knowledge of the type of fluids in the subsurface can be determined through chemical and isotopic analysis of volcanic gases. In this project, we aim to combine high temporal resolution measurements of volcanic gas composition and seismicity to help constrain the type of fluid associated with these unique seismic signatures. A two-week field campaign was conducted between July 10 – 24, 2013 at three persistently degassing and seismically active volcanoes within the Katmai Volcanic Cluster (KVC), Alaska, to address this problem. The aims of this work were to collect samples of volcanic fluids for chemical and isotopic analyses and to install campaign instruments to measure gas composition, seismicity, and SO₂ flux at high temporal resolution at Mount Martin, Mount Mageik and Trident Volcano.

Another day on the field. Francesco Capecchiacci, (from National Reseach Council, Italy) hikes along Mount Martin’s crater rim. Mount Mageik can be seen in the background. The photo was taken in July 2013 by Taryn Lopez during a two-week field campaign conducted in the Katmai Volcanic Cluster in Alaska.

Part 1:
Volcanic gas and seismic instrument installation

July 10, 2013 – After months of planning, the field campaign for my NSF GeoPRISMS postdoctoral fellowship project was about to get underway. Things were off to a reasonably smooth start with both my field partners Bo Galle (Chalmers University Sweden) and Francesco Cappechiacci (National Research Council, Italy) having arrived safely to Alaska and our team en route to King Salmon, Alaska, the closest town to the KVC. We were met in King Salmon by my Alaska Volcano Observatory (AVO) colleagues Dane Ketner and Max Kaufman, who would be conducting maintenance on the AVO Katmai seismic network and assisting with the instrument installations that were critical to my project. After making some last-minute purchases at the local store, my team headed to the hangar of Egli Air Haul, the local company that has provided helicopter and fixed wing service to AVO for fieldwork in Katmai for over 20 years. Our plan was for Francesco, Bo and I, along with our 600+ lbs. of instruments, food, and field gear to get transported to the famous Valley of Ten Thousand Smokes (VTTS), the site of the largest volcanic eruption of the 20th century, the 1912 Katmai-Novarupta eruption. We would set up our base camp at the USGS Research station on Baked Mountain. Dane and Max would be staying in King Salmon for the next six nights and would fly in each day with Sam Egli, our helicopter pilot. Due to weight restrictions my team would be shuttled to the VTTS on a fixed-wing airplane in two shifts and would then have to hike our gear two horizontal miles and 400+ vertical feet from our landing spot to our base camp. We decided that Francesco and I would go in the first shift and start shuttling our most critical assets to camp. The trip to the VTTS was beautiful and we were lucky to have fantastically clear skies allowing for impressive aerial views. Francesco and I began the first of three slow slogs to camp, while our pilot returned for Bo. By 11:00 PM (or approximately 7 hours after departing King Salmon) we had finally transported ourselves and all our gear to camp. We were exhausted, but happy to be there, and had arrived just in time for a beautiful sunset!

Figure 1. View of Mount Mageik (center) and Mount Martin (right, with plume) as seen from Baked Mountain on 11 July 2013. Photo credit T. Lopez

July 11, 2013 – We awoke to beautiful clear skies, low winds and open-summits at both Martin and Mageik (Fig. 1). Favorable weather conditions like this are atypical of the Alaska Peninsula and we were feeling optimistic that we would complete our field objectives. It was our first of seven days of helicopter support (shared with AVO) during which time we aimed to complete the following tasks: (1) Install MultiGas instruments for measuring volcanic plume composition (CO₂, SO₂, H₂S, and H₂O) and broadband seismometers on the summits of Mount Martin, Mount Mageik, and Trident’s southeast fumarole field; (2) Install scanning NOVAC instruments for measuring continuous SO₂ flux downwind from Mount Martin and Mount Mageik; and (3) Directly sample the fumarolic emissions from Mount Mageik, Mount Martin and Trident Volcano. Additionally, our USGS colleagues also needed to service several seismic stations. Our plan was ambitious but if the weather cooperated it would be achievable.
At 8:00 AM I made my morning check-in call to Dane, who reported that the weather was also clear in King Salmon and he hoped that they would be flying soon. While much of the first day was spent shuttling batteries, instruments, and station enclosures from King Salmon to the Baked Mountain Camp, by 7 PM that evening, Dane and I finally arrived on the summit of our first target, Mount Mageik. With help from Sam, our pilot, we managed to get much of the hardware for our co-located seismic and MultiGas station installed by 9 PM.

From top to bottom: Figure 2. (a) Francesco Capecchiacci samples volcanic gases in the crater of Mount Mageik. (b) Francesco Capecchiacci hikes up from the crater of Mount Mageik. (c) Sam Egli and Taryn Lopez on the crater rim of Mount Martin. Photos credit T. Lopez

July 12, 2013 – The next morning, we awoke to similarly glorious conditions! By noon, Sam had dropped Dane and I off at Mageik’s summit to complete our work. While we continued working on the installation, Sam shuttled Max and Bo to the proposed site for installing the Mageik NOVAC station and then brought Francesco to join us at the summit. Francesco and I were hoping to hike down into the crater of Mount Mageik to sample the fumarolic gases and crater lake water. Working on active volcanoes can be a hazardous job, especially for gas geochemists who often need to spend time within active craters to get the most useful samples. Mageik’s steep-sided crater walls and abundant gas emissions which could eliminate visibility with the slightest wind-change, induced what I hoped was just the right amount of caution to allow us to be successful and stay safe. The wind was blowing the plume to the south, which meant that we had good visibility and access to the fumaroles on the north crater wall. We scrambled fairly easily down the soft, highly altered volcanic rock that comprised the crater walls and set up to begin sampling the gas and steam condensate from a boiling point temperature fumarole (Figs. 2a, 2b). Two hours later we had completed sampling of two fumaroles and took advantage of a brief parting of the plume to scramble down to the crater floor and quickly sample the quite warm and acidic crater lake water. At 5:30 PM we rejoined Dane on the crater rim who had much of the instrument installation completed. After configuring and acquiring the first test data from our instruments, we headed back to camp. Bo and Max had been equally successful and installed the NOVAC instrument in under three hours. It was a good day!

July 13, 2013 – We woke up on our third helicopter day to another beautiful day. The summit of Mount Martin, our next target, was open providing nice views of its persistent plume, and we were eager to begin our work. We adopted the same plan as the previous day and were almost as successful. The one major disappointment of the day was that Francesco and I were unable to sample the vigorously degassing and audibly jetting fumaroles within Mount Martin’s steeply sided crater. We scouted our options from multiple vantage points along the crater rim. Unfortunately most of the crater walls were nearly vertical and comprised of highly weathered, unconsolidated material, with regular outcrops of overhung volcanic rock. We realized that rock falls would be a hazard for all viable routes. With much disappointment, we decided that sampling the Martin fumaroles was not feasible. We were successful in installing the summit seismometer and MultiGas instrument as well as the down-wind NOVAC station and concluded that it was still a very successful day (Figs. 2c, 3)!

Figure 3. Mount Martin co-located seismic and MultiGas station with Mount Mageik in the background. Photo credit T. Lopez

July 14-18, 2013 – The weather conditions over the next several days deteriorated, with high clouds covering most of the summits, and a dense cloud build-up behind Katmai Pass – the gate to our last field target, Trident Volcano’s southeast fumarole field. Bo, Francesco and I spent much of this time at camp, downloading data from the NOVAC stations, and allowing Max and Dane to work on AVO seismic network maintenance. Luckily we had a few nice windows of opportunity during this time period and were able to install the MultiGas sensor and collect fumarole samples at Trident Volcano before having to say goodbye to Bo, Max, Dane, and Sam on July 18. Francesco and I had four more days to hike around the VTTS and collect water samples.

At the end of the July field campaign we had completed 7/8 of our proposed instrument installations and collected gas samples at 2/3 of the proposed volcanic fumarole fields. This was the most ambitious volcanic gas geochemistry effort to take place in Alaska since the 1990’s and we felt very happy with our accomplishments! Our plan was to leave the campaign instruments running over the next two months of summer and then to retrieve the instruments and data before fall arrived in September.

Figure 4. Summit of Mount Mageik as seen flying in on 4 September 2013. Figure 5. (left) The Mount Mageik MultiGas station as found on 4 September 2013. Photos credit T. Lopez

Part II:
Two days stranded on Mount Mageik

September 4, 2013 – I was back in King Salmon with my AVO colleague, John Paskievitch, who had offered to help me retrieve the instruments that my team had installed earlier that summer and who would also conduct some additional AVO maintenance on the Katmai seismic network. It was our first of three scheduled helicopter days to conduct this work and, unfortunately, the weather forecast for this field campaign was not encouraging. After running a few errands around town, John and I headed to Egli Air Haul to meet Sam and to weigh and organize our field gear. By early afternoon, the fog had thinned and we decided to fly to the VTTS to see if any fieldwork would be possible. To our surprise, the valley was clear and Mount Mageik’s summit was open (Fig. 4). After a quick stop at the Baked Mountain Huts to drop off any unnecessary weight and to get into our warmest clothes, we flew to Mount Mageik’s summit, arriving at ~3 PM.

Our station was located on a small hill between Mount Mageik’s four summits, on the rim of the actively degassing crater and surrounded on three sides by heavily crevassed glaciers. Upon our arrival to the station, John and I found that the station enclosure had become unlatched, was open, and the instruments and the station antenna mast were completely covered in thick rime ice (Fig. 5). We had blue skies above us but a dense wall of clouds was building up on the south side of Mount Mageik, and we knew that we had to watch the weather closely, as conditions could change very quickly. Sam stayed in the helicopter and watched the weather while John and I began to extract the instruments from the frozen ground. Approximately 30 minutes later Sam told us that the weather had deteriorated and we needed to leave NOW!

Clockwise from top left: Figure 6. (a) John Paskievitch as seen on 4 September 2013 after securing the helicopter with snow anchors in preparation for spending the night. (b) Helicopter covered in thick rime ice after ~16 hours on the summit of Mount Mageik (5 September 2013). (c) Alaska Air National Guard Rescue team and Pavehawk helicopter on Mount Mageik. Photos credit T. Lopez

John and I grabbed our equipment and helmets and were back in the helicopter in less than four minutes. Unfortunately, in those few minutes the clouds had rolled in, bringing with them freezing rain. Sam powered up the helicopter and we sat ready to take off at the first sign of improved visibility, while the helicopter blades were gradually accumulating ice. Approximately 15 minutes later, having had no improvement in visibility, Sam realized that the rotor blades had too much ice to fly. Sam powered down the helicopter and John and I made several futile attempts to scrape ice off the rotor blades. Conditions continued to deteriorate, and we realized that we would have to spend the night on the mountain and we would likely require rescue as our helicopter would probably not be flyable due to ice accumulation. We called Egli Air Haul and the AVO duty scientists to inform them of our situation and to ask them to notify the Alaska State Troopers.

In any survival training course you will learn that the first thing you should do in an emergency situation is to secure shelter. We were lucky to have brought our shelter with us, but with the high winds our helicopter was at risk of being blown down into the crater. Therefore, with Sam and I sitting in the helicopter to keep it weighed down, John spent several hours securing the helicopter with “dead-men” snow-anchors (Fig. 6a). By 9 PM our shelter was secure. Our next priority was simply to stay warm and dry, conserve energy, and wait for rescue. Thankfully we were well prepared for an emergency situation and had sufficient clothing, sleeping bags, sleeping pads, bivy-sacks, food, water, and communication supplies to keep us comfortable, at least in the short term. We also had a combination of ~55 years of experience doing field work in Alaska and I was very grateful for my highly experienced and resourceful comrades!

September 5, 2013 – After a fitful night of sleep with strong winds peaking at 75 mph, we woke to similarly dismal conditions, with continued freezing rain and poor visibility. We also found that the entire helicopter was covered in ~8 inches of rime ice, making it difficult to open the doors and even causing the helicopter’s frame to distort under the excess pressure (Fig. 6b). We passed the day quietly, dozing a lot, talking some, going outside as infrequently as possible, and looking forward to our regular satellite phone check-in calls with Egli Air Haul. By 5:00 PM that day, there was no improvement to the weather and no external rescue efforts had been planned. We realized that our situation could easily go from uncomfortable to life threatening if we were not rescued soon, especially considering that our shelter was at risk of being compromised with the increasing ice-load. At that point Sam turned on the helicopter’s Emergency Locator Transmission. Within an hour we received word that the Alaska Air National Guard (AANG) was mobilizing rescue teams. At 9:00 PM that evening we first heard the comforting sounds of our rescue aircraft nearby. The AANG had deployed two rescue teams to assist us. One team based on a C-130 airplane was flying over our position, looking for any potential breaks in weather, while the second aircraft, a Pavehawk helicopter, contained our ground-support team. Using our helicopter’s radio we were able to directly speak with the AANG pilots and set up regular check-in times to communicate with them in case of potential weather breaks. Unfortunately, a thick layer of clouds continued to keep us trapped through the night. We spent a second night in the helicopter, colder and less comfortable than the first, but encouraged by the regular sound of our rescue aircraft nearby.

Panoramic view from the North of the Katmai Volcanic Cluster. Photo credit T. Lopez

September 6, 2013 – By 8:00 AM the next morning, the winds had dropped significantly and the temperature was rising. Most encouraging of all was that visibility had increased to ~20 m and the sky was brighter indicating a thinner cloud deck. By noon, the ice on the helicopter frame had begun to melt. Over the next three hours the Pavehawk helicopter flew back and forth over our location hoping to catch a break in the clouds and sweep in to rescue us. Using our hand-held USGS radios and the sound of their rotors, we helped them narrow in on our position. The clouds continued to thin and we were finally rewarded with the welcome sight of their massive helicopter! Minutes later, the Pavehawk had landed on the glacier below us and two of our rescuers, tethered to the Pavehawk, quickly crossed the glacier to meet us and escorted us back to safety (Fig. 6c)!
Our experience on Mount Mageik went about as well as it could have thanks to Sam’s resolve to not fly in unsafe conditions, John’s resourcefulness in anchoring the helicopter, our preparation with survival gear and training, an excellent support/communication team at home, and the competency and bravery of the AANG rescue team. I feel very lucky that all of these things came together so that I have the opportunity to share my story today. While I learned many important life lessons during this experience, I would like to share two of them here: (1) Spend as much time as possible with your loved ones as you never know what day will be your last, and (2) Fieldwork in Alaska should never be taken lightly, so ALWAYS carry your survival gear and have proper training! ■

“Report from the Field” was designed to inform the community of real-time, exciting GeoPRISMS -related research. Through this report, the authors expose the excitement, trials, and opportunities to conduct fieldwork, as well as the challenges they may have experienced by deploying research activities in unique geological settings. If you would like to contribute to this series and share your experience on the field, please contact the GeoPRISMS Office at info@geoprisms.nineplanetsllc.com. This opportunity is open to anyone engaged in GeoPRISMS research, from senior researchers to undergraduate students.
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