Woods Hole Oceanographic Institution

Science at Sea

A hypothesis is a proposed explanation for a phenomenon, but a scientific hypothesis makes predictions and is testable. The MESH expedition is testing hypotheses about the origin and history of large submarine eruptions.

Because we are trying to understand the unknown, our hypotheses are sometimes wrong or, in hindsight, just misguided. In my own research–on land–we usually have to do experiments or carry out field studies several times to properly formulate questions and answer them. Although we begin with a hypothesis, in the process of addressing it we typically refine the question and the research methodology.This process is repeated until we have a clear question and answer. Read More →

A Crystal’s Journey Through Middle Earth

Pumice and lava are the cooled, hardened versions of bodies of molten rock and crystals stored beneath the seafloor that geologists call magma. Prior to being sampled by Jason, volcanic rocks on the seafloor north of New Zealand have experienced long and arduous journeys as magmas, venturing through Middle Earth (much like Frodo Baggins). The ‘Middle Earth’ in our story is the upper portion of Earth’s mantle and oceanic crust where these magmas accumulate, form crystals, and rise to the seafloor, where they erupt.

Between its initial formation and its final stages, a body of magma undergoes a series of changes caused by the formation of crystals, as well as interactions with other magmas and with oceanic crust. In order to understand this epic tale better, and to provide the prologue for why and how pumice and lava was erupted from Havre volcano in 2012, we must look for clues held in crystals found in the samples we are collecting during the MESH expedition. Unlike The Lord of the Rings, this story does not contain wizards or orcs but it does contain some tricky words, which are defined in a glossary at the bottom of this post. There is also a recipe for creating magma (do not try at home) that summarizes the different stages. Read More →

Lunar Eclipse

The Roger Revelle never sleeps, but we are supposed to do so at some point during the day or the night. I have the 4:00 a.m. to 8:00 a.m. and 4:00 p.m. to 8:00 p.m. shifts, so I usually go to sleep early in the evening to be in shape for the early wake-up (yes, I consider 3:20 a.m. rather early).


Lunar eclipse from the South Pacific. Photo by Martin Jutzeler

Today, we were alerted by the captain that a large part of the Pacific would experience a total lunar eclipse at 1:00 a.m. The last time I was on a research vessel, I  experienced a moon eclipse and greatly enjoyed the spectacle, so to enjoy it again, I had to reduce my my planned six hours of sleep to two.

The eclipse was absolutely beautiful, with a perfect sky, nice temperature, and gentle rocking ship. But photography was difficult. How does one capture a dark, distant object over a black background, without using a tripod? I had a good go with the manual settings on my camera.

It is now 2:30 a.m., and I am writing this blog post, waiting for my official wake-up time in one hour. I may have to make my coffee a little bit stronger than usual in the morning and go back to bed after breakfast time. But it was worth it.

What are Submarine Lava Domes?

So this expedition was supposed to be about Havre volcano exploding in 2012 and how the huge pumice rafts we all saw were formed. We will get to that eventually but so far, what we have found on the seafloor at the Havre is mostly new lavas. In fact, most of the world’s ocean floor is made of lava called basalt (plus a thin layer of sediment above that volcanologists like to ignore). Basalt lavas on the seafloor are commonly found in thin layers or in tube-like features known as pillow lava.

Although finding lava on the seafloor is no big deal, the Havre lavas are very different from the black basalt lavas and not at all common. They appear to be rhyolite. Rhyolite lavas have a chemical composition that makes them very sticky and stiff (viscous) when they emerge from the vent. Rather than flowing away, the pasty rhyolite lava piles up over the vent forming a mound (dome) that may grow to tens or even a couple of hundred meters high. If enough rhyolite comes out, then the dome may spread forming a short tongue of lava.

We have been using the autonomous underwater vehicle Sentry (a vehicle that can move underwater independently of the ship, collecting data) to make a very detailed map of the seafloor right at Havre volcano. The maps show new lava domes on the seafloor. We know for sure the Sentry features are domes because we have been down there with Jason, observed and sampled them.

So what do the rhyolite domes look like? They have an overall lumpy dome shape and close up, they look like big piles of jumbled up rock fragments, twisted blobs and jagged spires–in the words of one of the crew, “a big dump of sticky concrete.” Some of the spires are as high as 10 meters but only a few m across. All the rocky rubble comes from the sticky lava breaking up when it quenches and cracks up in the cold seawater. The broken pieces collect in talus around the edges of the domes and on the top. Most of the inside of the dome is solid rhyolite or broken just a little.

Only a few other rhyolite domes have been found and sampled on the floor of modern oceans because the rhyolite composition is not common. Rhyolite domes are reasonably common in volcanic areas on land. We know from the ones on land that sometimes growth of the domes is interrupted by explosions.

Life in the Dark

I’m always amazed by the abundance of life in the deep ocean. Even when we are focused on studying the volcanic features on the seafloor, we can’t help but get excited by seeing a squid, shark, or shrimp float by in front of Jason‘s cameras.

The range of animals we have observed on our dives so far include chemosynthetic microbial colonies that derive their energy from the chemistry of hot water venting from the seafloor (as opposed to the photosynthetic life we are accustomed to at the surface), scavengers that search the seafloor food, and animals of all types that cling to the rocks and feed on tiny animals floating by on the currents.

The animals that we find are beautiful in their methods of locomotion, their survival strategies, and their various forms, but they are also useful to us in the ways they help us understand the geology that is our primary focus.

For instance, when we were traversing a set of domes on the caldera rim, we found one that had a slow-growing coral attached to the rock. The coral indicates that that dome is much older than the others, as the delicate animal could not have survived an eruption and, in addition, took decades to grow to its observed size.

Microbial communities are a bright splash of color that help us identify places where hot water is seeping from the seafloor. The bright orange microbial mats we have found are likely a type of iron-oxidizing bacteria that have been found at other submarine volcanoes like Loihi off the coast ofHawaii. Without these mats it would be difficult to pick out vent and seep sites on the seafloor, the locations of which help us understand how the 2012 lava is cooling and how water circulates through the ocean crust.

Preparing the Elevator for a Dip

Once the ROV Jason begins collecting samples on the seafloor, we need a way to retrieve these samples as frequently as possible while Jason remains working underwater. This is where the elevator comes in.

IMG_2983A small team worked through sunrise, breakfast, and lunch today bolting down boxes and preparing the elevator for its first test dive. We recorded their operation to keep an eye on their progress (see below).

The elevator is a four-by-four-foot platform with collecting boxes and crates bolted to it, a weight mechanism that enables the elevator to sink, a tracking beacon to determine its location, and an incompressible, buoyant top of bubble-rich, low-density glass to bring it back to the surface.

After our team assembled the boxes, crates and respective lids to the platform, we fitted the elevator with a sensor to record water properties (temperature, turbidity), hoisted it over the side of the ship, and released it to sink down into the center of the caldera. The elevator will descend to 1600 meters beneath the surface before returning back to the ship.

Once we retrieve the elevator, we can begin with the next phase of our operations: deployment of Sentry and Jason.

Constructing the Elevator

Construction (above) and retrieval (below) of a deep-sea elevator on
board R/V Roger Revelle. Time lapse by Kristin Fauria, UC Berkeley

Retrieving the Elevator

Time lapse by Kristin Fauria, UC Berkeley

Launching Jason

This evening, at about 4:30 p.m. local time, the Jason Team launched Jason for the first time on this cruise. This remotely operated underwater vehicle will allow us to explore the seafloor and collect samples while we watch from the surface. More than a dozen scientists, engineers, technicians, and support staff make up the Jason Team and specialize in maintenance and operation of the vehicle. The team is based at the WHOI, but travels with Jason on expeditions around the world. Read more about the vehicle here and watch the vehicle being launched below.


The science team is extremely excited to see what Jason discovers and as it explores Havre’s caldera. Will it find obsidian, pumice, coherent lava bodies, hydrothermal vents, pyroclastic flow deposits, all of the above, or something entirely unexpected? We don’t know.

We do know that the types of rocks and deposits we find will not only tell us about the eruption that occurred here at Havre in 2012, but will also teach us about how volcanoes erupt underwater and why they sometimes erupt explosively. Until three years ago no one had seen an eruption like Havre 2012. Until now, no one has observed or made quantitative measurements of recent deposits from a deep, explosive submarine eruption. As a result, some very basic science questions have yet to be answered, despite the fact that the vast majority of volcanic activity on Earth occurring underwater

As I type Jason is descending descends to Havre’s caldera 1600 meters (1 mile) beneath the surface on the seafloor. In a few hours we may start making our first discoveries. A lot of effort and expertise from dozens of people and institutions has made this expedition possible, and to make the most of our resources, the science and Jason teams will be operating the vehicle around-the-clock.

The rock samples and observations from the Jason dives will be the first of their kind, and the data we collect may very well spawn new models for submarine volcanism and (at least this blogger believes) stand as lasting and substantial contributions to planetary volcanology.

We are nearing the bottom now and I can’t wait to get started.

Life at Sea

Just over 48 hours ago we set off from Auckland aboard the R/V Roger Revelle with our sights set on the Havre Seamount. The saltier members of the team (those who had participated in a few of these cruises) knew just what to expect, while the folks new to life aboard a research vessel are learning through their early experiences. Over the time it has taken for us to transit to Havre, we have accumulated a slough of new experiences and skills.

Seasickness and Sea legs
For many of us, the hardest part of this journey is adjusting to the motion of the ocean. Seasickness is a beast only Dramamine, adhesive medicine patches, and ginger tablets can tame. As many of us congregate in the library outside of the mess, we try many activities to distract us from the rocking of the boat. Reading, working, drawing on cups (more about this later), sleeping lying down, sleeping sitting up—really anything we can do to help.

Meanwhile, the more experienced among us say it will only last a couple days. Maybe it was slowing down and calming of the seas or being active on deck or maybe just knowing that we are close to starting some science, but today was the first day I think everyone is feeling all right.

The more exciting side of the process of equilibrating to the rolling ocean is the slow development of “sea legs.” For those who have never experienced this phenomenon, when you first try walking a straight line aboard a tossing ship, it is not easy. To walk straight you must adjust your center of balance with the sway of the ship (which isn’t always predictable). As you develop sea legs, you slowly progress from the walking capability of a waddling toddler to the occasionally smooth I-meant-to-do-that misstep.

In addition, showering is a very “interesting” experience. I think I’d compare it to trying to shower in a half-sized closet set up inside a tilt-a-whirl. Though it has taken a couple of days, we are all starting to walk straight lines again.

Waiting through transit
For the team leaders, the first few days have been filled with endless tasks and preparation. For most of the rest of us, our days have been filled with a few meetings and some minor tasks, but mostly just filling time as we wait to start our science. Some of the more focused members of our group can be seen eagerly punching away at their keyboards, maintaining high productivity levels even while combating seasickness.

For me, I choose to read. The library set up here on the Revelle is quite stocked with a range of books from Atlantia to Geophysical Fluid Dynamics. Reading is great for seasickness because it makes you focus on the text and not on the shifting room around you.

Aside from reading in the library, I have also spent a fair amount of time wandering through the maze of tunnels and corridors that is the Revelle’s insides. Without much to serve as landmarks, it is easy to get turned around. During my first day aboard, every trip outside of my quarters turned into a small adventure, similar to the game of chutes and ladders, minus the chutes.

The ship’s crew and food
At first, I didn’t know what to expect from the crew. Here are these men who live out on the open ocean more than they do on land. Many are grizzly and tough and bearded, though, so far, they are all extremely helpful and friendly. After many meals with many accompanying conversations, I have learned about the upsides and downsides of life at sea, plenty of maritime terminology, and tidbits of some of these folks’ lives. I look forward to these conversations at every meal.

I couldn’t bring up mealtime without throwing some high praise at Mark and Marc’s delicious seafaring cuisine. I had heard that the food on research vessels could be good, but I didn’t expect what we have aboard the Revelle. Each meal is a feast with fresh proteins and fruits and salads and starches and sides. I will be lucky to not gain ten pounds by the time we get back to land.

The transition to life at sea has been nothing short of interesting, but I am glad the MESH team is starting to get settled and comfortable. Today was Day 1 as far as having equipment in the water, and as soon as Jason and Sentry start gathering data and samples, we will need as many able-bodied (and able-minded) workers as we have aboard!

What is Pumice?

We’ll be spending a lot of time examining and talking about pumice on this trip, so we thought it would be a good idea to take a closer look at pumice now, before we get too busy.

Pumice is usually formed when volcanoes explode. Volcanoes explode when there are lots of gas bubbles trapped in the magma. As the gas pressure builds, it eventually causes an explosion. When that happens, the magma is torn apart into many small pieces that still have gas bubbles in them–we call these bubbly shards of cooled magma pumice. When it is still hot, the pumice and gas escape quickly from the vent, producing lots of explosions as they do.

If you live somewhere near an active volcano, you have probably seen pumice on the ground or in cliffs. If you don’t live near an active volcano, you still might have seen pumice because it often floats, thanks to of all the holes, and it can be found washed up on beaches far from the volcano that made it.

We have seen many explosive eruptions at volcanoes on land but only two very small ones at volcanoes under the ocean. This expedition is going to Havre volcano, which is entirely submerged. When Havre erupted in 2012, it produced a large amount of floating pumice so we know the eruption was explosive. Ocean currents swept the floating pumice along, some of it as far as the eastern coast of Australia. Pumice doesn’t float forever—water seeps slowly into the holes in the pumice, making it heavier and heavier until it sinks to the seafloor.

Floating pumice is relatively easy to find and study but freshly erupted pumice doesn’t always float, even though it is very light and full of holes. When the pumice coming out of a vent on the seafloor is very hot and just the right size, it can quickly soak up water and fall back down to the seafloor, so chances are that some of the pumice produced by Havre in 2012 is on the seafloor close to the volcano. In a couple of days, we will know for sure.

Once More Into the Deep

By James White

On Friday (New Zealand time), R/V Roger Revelle sailed from Auckland and we’re on our way to Havre Seamount to make seafloor observations and take samples from this newest known submarine volcanic deposit. This is my third trip, widely spaced over two decades, to study deposits of volcanic eruptions on the seafloor, but my first in which the team will deploy a remotely operated vehicle (ROV). It will also be, by a wide margin, the youngest eruption deposits that I will have seen on the seafloor.


James White on deck with ROV Jason.

My first trip, in 1995, was led by a scientist named Rodey Batiza and was among the earliest to employ the submersible Alvin to conduct a focused study of physical eruption processes. We made nine dives on that trip onto a small area of a volcano called Seamount Six to look at and sample a deposit type called “hyaloclastite,” which is made predominantly of small, angular chunks of basaltic glass only one or two millimeters across. Among these miniscule glass fragments are a small proportion of particles broken from very thin glass sheets, which were bent and twisted as they formed. The aim of the cruise was to test the predictions of a model from Rodey’s previous work that suggested these glass sheets are solidified remnants of fluid basaltic magma that was torn apart in submarine lava fountains.

To test this, we looked for the distinctive features of lava-fountain deposits on Hawaii, which are progressively thinner and made of smaller particles at greater distances from the fountain. These deposits also have an elliptical shape when viewed on a map and are elongated in the direction that the wind was blowing during the eruption.

Seamount Six deposits are estimated to be about 2 million years old, but the glassy particles are very fresh beneath, and partly held together by, a centimeters-thick layer of seafloor manganese, which looks like bulbous black moss or mold covering the deposits.

What we found over the course of nine Alvin dives was not what we anticipated. Instead of deposits that became thinner and composed of smaller particles at greater distances from what we inferred to be the source of the lava fountain at the top of the volcano, we found many small patches of deposits, all with about the same thickness and composed of roughly similar-sized grains, over distances of more than a kilometre. This told us that the deposits could not have been formed and dispersed from a single lava fountain.

We then looked for evidence of small lava-fountain sources, particularly small cones of “spattered lava in or near the individual deposit patches, but found none of these, either. Everybody agreed that the most likely origin for all of the blocky glass fragments forming 90 percent or more of the material in the deposits was quench-shattering of hot lava as it cam in contact with cold seawater, but we had no source for the small proportion of small glass sheets that were curved and twisted, even folded, that we thought came from lava fountains.

In one of our many interesting discussions, we realized that these small glassy sheets had a lot in common with much larger, but still very thin and glassy, sheets of basalt that form along the coast at Kilauea where water gets trapped in lava. The trapped water expands as it boils, blowing big bubbles, or balloons, of basalt that pop to form the thin glass sheets. Volcanologist Ken Hon named these formations limu o’ Pele when he wrote about the activity and described how they formed. Deep-sea limu are much smaller than those found on the coast because the great water pressure at Seamount Six depths (1700 to 2000 meters) prevented the boiling water trapped in its basalt bubble from expanding very much at all. It was an interesting and unexpected outcome of my first trip to the ocean floor, and I immediately began trying to arrange another submarine project.

My second trip was over a decade later, in 2006, and was led by Bruce Houghton, who had joined the University of Hawaii from New Zealand just as Rodey left Hawaii for a new position on the mainland. Bruce, a PhD student I was supervising in New Zealand, and I made series of dives with a different small research submarine, Pisces IV, operated by the Hawaii Undersea Research Lab, onto the surface of Loihi seamount. Loihi is the youngest Hawaiian volcano lies lies underwater a few tens of kilometers southeast of the Big Island’s Kilauea volcano. On that cruise, we revisited seafloor deposits where another volcanologist, Dave Clague, had described layered outcrops of volcanic particles that found in small hills built on top of Loihi. Our aim was to sample the outcrops very systematically and then look at the internal textures of the particles to determine how the deposits formed. Rebecca Carey, the cruise co-chief scientist for the Havre expedition we are on now, also took part in the dives.

In one deposit on Loihi, we found more limu associated with a very thin lava flow, but the main samples we took were bubbly basalt glass fragments a few centimeters across. By measuring the volume, shapes, and sizes of the bubbles in different fragments; examining the shape of small grains with a scanning electron microscope; looking at the shapes of tiny crystals; and analyzing the chemistry of the glass, the crystals, and of small blebs of glass that had gotten trapped inside crystals as they grew before the eruption, my student Ian Schipper was able to determine that different small hills were cones from different eruptions. He also showed how the different eruptions behaved, and that, for at least one of, them magma-water explosions must have broken up the erupting magma. The Loihi deposits don’t have thick manganese layers, and are generally much fresher than those at Seamount Six, and, though we don’t know the deposit ages, it is inferred that these deposits are young—perhaps hundreds to a few thousands of years old considering how quickly Loihi has been growing—and much younger than at Seamount Six.

This trip we’re on now to Havre will be a great adventure, but if I hadn’t had the opportunity to study those other submarine volcanoes, I doubt I would be here. There are not a lot of physical volcanologists who study submarine volcanoes, and there have been very few submarine eruptions that we know of historically. This isn’t because there are very few eruptions–in fact, most of Earth’s volcanic activity occurs underwater—it’s because the ocean is vast and seawater covers these volcanoes obscuring eruptions from us on the surface, even if someone is in the vicinity.

The story elsewhere on this site, about how people found out about the Havre eruption, provides a great illustration of how different it is to study submarine volcanoes compared to those on land. And now, after I’ve worked with a 2-million-year-old deposit, and one perhaps only hundreds or thousands of years old, I’ll finally get to look at a fresh one, from an eruption that we know quite a bit about already. This time, however, we won’t be collecting samples from a, so I won’t get another visit to one of Earth’s least-visited realms, but the ROV is much more efficient. Watching the big screens from the ship’s control room will actually provide a better view than you get “live” looking out of the portholes of a research submarine—plus you don’t have to hold your bladder for six or eight hours!