We are back on land! We docked in Honolulu bright and early on the 20th of December, bringing our long and productive voyage to an end. In total, we travelled 10380 nautical miles (that’s 19,224 kilometers, or just 810 km short of going halfway round the planet!) over 47 days afloat between casting off in California and tying up in Hawai’i. This science came with a real cost: the good ship R/V Roger Revelle clocks in at a sturdy 540 ft/gallon, so we went through quite a lot of diesel.
The last few days of the cruise were spent processing and cutting up dredge rocks, preparing gear for shipping, consolidating seismic data, and enjoying the last moments of mask-less socializing. As a reward for our sustained efforts, we watched all of the Lord of the Rings movies – extended editions, of course – and consumed approximately 1000 bags of popcorn. It has been a remarkable privilege and pleasure to revel in “normal” human interaction, playing boardgames, singing, eating together, in our pandemic-free bubble for the last few weeks. This cruise has been a microcosmic example of how smart health protocols and strict individual adherence are the keys to controlling spread of this pernicious virus; we are so grateful for the careful planning that allowed everyone to stay healthy and accomplish our science.
Quickly turning around a dredge between sites – while one team processes rocks, another lifts the basket, getting ready to repair and redeploy. Photo credit: Sean McPeak.The team enjoys an afternoon in the sun, knotting a new net to go inside the dredge bag (the previous, much-loved, net had seen one-too-many dredges and dropped any rocks it had been holding on the way up). Photo credit: Zach Eilon.
Scientifically, this expedition has been a phenomenal success. As you’ll recall, the two primary objectives of this cruise were to recover 30 broadband OBS instruments deployed last year, and to dredge three seamounts in American Samoa. The secondary objectives were to conduct detailed multibeam bathymetry mapping and to dredge seamounts in the OBS array area. All of these goals were met, and thoroughly exceeded! We safely recovered all of the OBS instruments, and found that the vast majority of them contained a year’s worth of high-quality seismic data. We are still (and will be for years!) analysing the waveforms, but even a cursory analysis shows nice quiet stations and very clear earthquake arrivals. It is no exaggeration to say that this is one of the most complete and detailed broadband seismic datasets ever collected from the world’s central oceans.
We will use this data in its many forms – both earthquake signals and the random (but coherent) “noisy” background signals – to make images of the Earth’s interior. These images will teach us about the structure of the oceanic tectonic plates and, ultimately, how they move around. We also produced a comprehensive new seafloor map, improving on the bathymetry resolution from satellite data by more than two orders of magnitude over the huge 250,000 km2 region spanned by our seismic array. The dredging operations were so efficient that having planned for 3 dredges overall, we were able to complete 11 total dredges, bringing up plenty of seafloor basalts and even some bonus shark teeth! These rocks will fill in crucial gaps in our community’s understanding of how the Pacific plate has interacted with deep-seated jets of hot mantle that tap our planet’s primordial depths. Not to be accused of sitting on our hands during the long transits, we also collected rainwater and seawater samples at least daily, and gathered magnetic and gravimetric data throughout the cruise.
All of this marvellous success came thanks to our capable research techs and scientists. As chief scientist, I am allowed to brag a little about our wonderful team: I cannot imagine spending seven weeks at sea with a more enthusiastic, conscientious, good-natured, and lovely group of scientists. They were just as zealous about completing the small repetitive tasks as the blue ribbon operations. They did not shirk from – and actually seemed to prefer – the messy tasks, and their ethic of happy hard work was infectious.
This is what a crack OBS recovery team looks like. Photo credit: Erica Nathan.
Likewise, none of our work would be possible without the world-class research platform that is the R/V Roger Revelle, which allowed continuous operations in challenging sea states, and without the diligence and casual excellence of her research technicians and crew. What is, for some of us, a once-in-a-lifetime adventure into the middle of the vast ocean is actually just another day in the life of these professional mariners. Their unflappable workmanship (and willingness to inhale ghastly quantities of ship’s paint) is the undergirding of all marine science. We are grateful to them for keeping us productive and safe.
We encountered some stormy seas, but the R/V Roger Revelle weathered them comfortably. Well, it was mostly comfortable. Photo credit: Zach Eilon.
This expedition was the last of four for the Pacific ORCA (OBS Research into Convecting Asthenosphere) experiment. As the sun sets on this component of the project, we can look back with satisfaction. We have deployed and recovered two large seismic arrays in remote tracts of the central oceans, and now go to work analysing the data, which will provide fodder for many manuscripts and student theses for years to come. These four cruises have involved a wide community of scientists, most of whom (including your writer) sailed for the first time in association with this project. In addition to the two PIs (Jim Gaherty and Zach Eilon), four other research faculty, five OBS research technicians, three postdoctoral researchers, and 23 graduate students sailed on one or more of the research legs. All have been superb shipmates.
Every member of our science parties down the years has signed this OBS, with its original artistic brilliance from Carlos Gomez on deployment #1. Wherever this little block of syntactic foam goes next, it will remember Pacific ORCA. Photo credit: Erica Nathan.
I hope you have enjoyed reading about our adventures – if you want to keep up to date with the progress of the research project, please check back here for periodic updates.
Signing off, for the entire extended Pacific ORCA team (old and new), Zach Eilon, Chief Scientist for this recovery cruise, and project co-PI
Like a lonely OBS coming back to the surface after its watery sojourn, our science team is happy to be back on land. Photo credit: Zach Eilon.
The trip is close to winding down, and what an adventure it’s been! It has come to our attention that thus far, this has been a very seismology-dominated blog. It’s only fair, then, to devote some time to another worthy scientific goal of this cruise: seamount dredging.
If you look at a map of the Pacific Ocean, you’ll notice that it’s dotted with tracks of little volcanoes that form islands, such as Hawai’i, Tahiti, or our beloved Marquesas (see Helen’s post). These tracks continue beyond the island chains; when the volcanoes don’t quite reach the surface, we call them seamounts. Besides hosting some beautiful tropical paradises, these volcano chains are interesting because they suggest hotspot volcanism, that is, volcanic activity that originates far from tectonic boundaries and may be related to mantle plumes that come from deep within the Earth.
A map of the Pacific Ocean from Finlayson et al. (2018), showing the variety of hotspot tracks that scour its surface. The many crossing and overlapping tracks near the star labeled “Samoa” demonstrate the complexity of these hotspots. It is our hope that the samples collected will help shed light on their origins.
Geologists have long asked questions about the nature of hotspots, such as: Are different hotspot tracks related to one another (specially in the South Pacific)? How deep in the mantle is the source of plumes, and what material do they drag to the surface? How do plumes change over time? To answer these questions, we can turn to chemical analyses of rocks from hotspot volcanoes. But to do those analyses… we need some rocks! As you can probably imagine, it’s an enormous challenge to obtain samples from underwater volcanoes, especially remote ancient seamounts in the South Pacific.
Enter team OldORCA and the R/V Roger Revelle, here to save the day.
All hands on deck! Zach smashes a rock fresh from the seafloor, while the rest of us scramble to reset the dredge basket and send it down once more. Photo courtesy of Sean McPeak.
UCSB professor Matt Jackson, who is ashore but represented among our science party by his student Lindsay, has done lots of work on the geochemistry of Pacific seamounts. He has picked out several seamounts for us to target for rock samples using a dredge. Basically, a dredge is a big metal claw that is open at both ends. One end (hopefully) scoops up the rocks, and the other is attached to a chain-link bag, lined with a dense fabric mesh to catch all our scoopings. We lower the whole contraption from the ship on a very strong wire, using a giant winch, all the way to the seafloor. In some cases, this might be as deep as 5000 m below sea level and it can take 90 minutes just to reach the bottom. The boat will then maneuver slowly up the flank of the seamount, and drag the dredge along the bottom. On board, we closely monitor the tension in the wire to know when the dredge might be catching rocks, and to make sure a “weak link” hasn’t broken – a fail-safe release in case the dredge gets tangled on a submarine outcrop. We cross our fingers and hope that the basket will be full when we pull it back on board.
Team #MorningShift in action, tagging the dredge basket. Photo courtesy of Erica Nathan.
We junior scientists had the chance to help with taglines and operate the A-frame to deploy the dredge and to bring it back on board. Once it is safely on deck, the fun begins: if we’re lucky enough to have collected rocks, we grab the nearest sledgehammer or rock hammer, and start smashing them apart. Besides being a good form of stress relief, it’s important to do this because rocks at the seafloor are often heavily altered by reactions with seawater, and a thick ferromanganese crust surrounds most of the samples we have collected. Lindsay is interested in looking at isotopic ratios of elements like argon, lead, strontium, neodymium, and hafnium, in order to date the rocks and characterize the volcanoes that formed them, so it’s important to have clean, unaltered crystals.
We did a few practice dredges at seamounts in our OBS array, and later headed northwest to American Samoa to search for treasures there. Some of these seamounts had not been mapped before the ORCA experiments, so it was exciting to chart them in detail with our multibeam, decide where to dredge, and bring up samples all in the space of a few hours. We also had the chance to name some of the new seamounts. A very special one was christened McPeak Peak, in honor of the birthday of OBS tech Sean, our friend and cruise spiritual leader.
An astonishing assortment of rocks were recovered: an array of green, black, brown, and grey rocks. Some were manganese nodules; some basalts with tantalizing olivine and clinopyroxene crystals; some very coarse-grained; some very fine; some highly porous and light-colored; and even a few errant shark teeth. It was as if Christmas came early!
A sampling of the rocks recovered. Left: A few different basalt candidates held together within manganese crust. Right: A mysterious porous rock. It looks like a dinner roll, but does not taste like one*. Photos courtesy of Erica Nathan.
At the start of the trip, we were hoping to get three dredges in, but all in all, we managed to complete 11 individual dredges at 8 different seamounts. That was all thanks to the careful planning that went into this cruise, the expertise of the research technicians, and the hard work and cooperation of the science party! Our last dredge ended with stormy seas and torrential rain, but also a truly enormous chunk of the seafloor and a happy group of scientists. On that high note, we completed our science objectives and turned our course northwards to Honolulu, and home.
Eva Golos, on behalf of the Old Pacific ORCA recovery science team
P.S. For more information related to the scientific goals of the dredging, please check out Lindsay’s paper (Buff et al. 2020), currently in press for publication in Geology.
The science party, soaked but happy, after our final dredge in American Samoa. Photo courtesy of Helen Janiszewski.
Good evening (or morning?) geo-readers! Time is an illusion on #nightshift, but we still have the pleasure of enjoying sunrises and sunsets seemingly whenever we so choose. The brilliant display of colors in the clouds, the addition of wildlife, islands, the moon, or even a rainbow dramatically changes the beauty we see. With so sunsets and sunrises, how do we determine which ones are superior? How do we quantitatively compare one day to another? We do what geologists, geophysicists, and geochemists do best! We characterize the quality of sunsets much like the magnitude of an earthquake.
Earthquakes are a destructive force releasing millions of joules of energy through the Earth. In the “far field”, thousands of miles from the epicenter, we can use this energy to image the Earth’s interior for our Pacific ORCA project. In the “near field”, it can destabilize buildings and generate tsunamis. Earthquakes are one of the greatest natural hazards we have to worry about not only as geoscientists, but as human beings on this planet. Sunsets are perhaps one of the greatest natural blessings on Earth and are a cosmic delight with marvelous colors. Over the years there have been many ways to describe the effects of earthquakes and the equivalent energy release. We now use the same magnitude scale for earthquakes to rate how badass the sunsets and sunrises are.
On the left a magnitude 6.2 sunset, clear visibility of the sun and potential for green flash. Not enough cloud cover to spice up the colors. On the right, “casually excellent” sunset, the crepuscular rays shine down on the ocean for a magnitude 6.9 and could’ve been a 7 at one point, the clouds needed to part a tiny bit.
Let me remind you, geoscience reader, what magnitude means for earthquakes. Historically, the Richter Scale was the most popular measure of earthquake magnitude, quantifying it by the amplitude of the produced wave. Of course, there are other ways to measure earthquakes such as the energy or intensity, but we can neglect those right now because I want to. Obviously, the Richter Scale is not commonly used anymore, except for short-period surface waves from local small earthquakes. Moment magnitude has been the front runner in the Geoscience Next Top Magnitude competition. All the physical properties and waveforms recorded from the shaking are used in the analysis of moment magnitude. The moment magnitude is calculated by multiplying the seismic moment (strength of the rock, area of fault slip, and distance the fault moved) by a constant and subtracting another constant to create a scale roughly equal to the Richter Scale. On average, magnitude 3 and smaller earthquakes rupture several hundred times a day around the world. Earthquakes with magnitude greater than 6 (1000 times stronger than magnitude 3), occur somewhere on the planet roughly once a month. “Great earthquakes, magnitudes 8 (100 times stronger than a magnitude 6) and higher, occur less than once per year, on average.
If you have been following our ORCA journey closely, you’ll see this as one of the Marquesas Islands and my picture might not do it justice, trust me, it was a magnitude 9.1. We just needed more dolphins.
Sunsets operate on the same rarity and intensity scale as earthquakes. You will see plenty of low-grade sunsets in your life, the ones that are a little humdrum and blocked by clouds. Then there are those days where the clouds are in the perfect position and you’re on top of a mountain with a baby eagle flying over your head while a bear catches fish from a stream. It may only happen once a research cruise, or may even take many research cruises, but when the universe aligns perfectly you get a truly magnificent “Great sunset”.
A magnitude 7.2 sunrise. Can you believe this is what we actually saw?No visible sun, but vibrant colors to match on this magnitude 5.8 sunrise.
Large earthquakes involve high fault slip, areas, and rock elasticity. A high magnitude sunset requires a plethora of radiant colors and expertly positioned clouds. Islands (or wildlife) make a nice addition. Others may disagree (many discussions occurred) on how exactly to record a particular sunrise or sunset on my scale, but ultimately a sunset’s magnitude is in the eye of the beholder. Our fearless leader Chief Scientist Zach most eloquently points out some sunsets are “casually excellent”, as with the Magnitude 9 we saw transiting past the Marquesas Islands. Witnessing a sunset over a spectacular jagged island with clouds to focus the breathtaking crepuscular sun rays is a once-in-a-lifetime sort of experience.
Easily a Magnitude 7.5 sunrise (maybe even a 7.8!) with the gradient sky and moon giving us a little peak. Sunrises generally only visible by #nightshift and #nightshift adjacent members.
I come from the desert with magnificent sunsets on watermelon mountains (Sandia Mountains… Hi Mom and Dad! Hi grandma!) but when the sun reflects off the water and the clouds are positioned just right, nothing else really compares (unless you’re my future wife reading this). Unfortunately, I cannot use sunset pictures to pay rent or I would be a rich man now. We must continue on back home so that I may use the data we just collected from the seafloor to weave through this thing called life. While the sun may inevitably set on our cosmic voyage through the universe, and our voyage on the vast ocean, we still may be humbled by the mysteries within our little blue planet.
All photos are unedited and were taken by your charming writer Joey Phillips. For more information about earthquakes visit https://earthquake.usgs.gov/
‘Twas the night before Thanksgiving on the Revelle, not a zephyr of wind nor a wave nor a swell. Only three scientists stirred, on the vessel adrift, but they’re more than a match for the rest, they’re Night Shift!
Their hard hats were hung by the doorway with care, in hopes that an OBS soon would be there. The day shift were nestled all snug in their beds, while visions of multibeam swam through their heads.
And with one more station checked off on the map, our co-chief (that’s Helen) went down for her nap. When all through her cabin arose such a clatter- it was not the bow thruster, so what was the matter?
Away to the lab she flew quick as a thing, straining her ears to hear multibeam’s ping. But down in the lab she saw quite a strange sight, And so she asked Joey if things were all right.
When what to her wondering eyes should appear, but Sean and his Edgetech: “It’s rising! It’s near!” Now the ResTechs assembled ever so quick, and fastened their taglines to each metal stick.
One tagline hit, attached to the crane, while the others reset to try once again. Then upwards and upwards the sensor ball rose, while sweet Justin grabbed the freshwater hose.
Get the temperature gun! Now take down the red flag! Then ratchet the pallet and remove the tag! Away with the logger they hastily scurry: we must sync the clock or else Peter will worry.
The pallet jack transports the float to the deck, while each box on Zach’s list receives a new check. We fasten the logger back into its hole. The techs go to sleep; they’ve accomplished their goal.
Then out to the port winch, a ResTech we’ll need deploying the Mag as we come up to speed. Helen begins microseismic inspection, rejecting the noise to see small scale convection.
The multibeam squeaks out another shrill whistle, proceeding to map all the plains so abyssal. Zach trades shifts with Helen just after first light. She says, “We got another! Now have good night!”
Erica Nathan, featuring Helen, Joey, Pete, Sean, and Sweet Justin, with Zach Eilon, and Lindsay Buff
Sean prepares his tagline pole for another OBS recovery. His excellent hard hat is even decorated to look like an OBS sensor ball!Co-chief scientist Helen in the process of getting her tagline onto the OBS during our final recovery of the voyage.
Ahoy! Much like whales or a calm day at sea, I am a rarity on the Roger Revelle: the sole geochemist in a sea (pun intended) of geophysicists. My role on this cruise is primarily to help with dredging – collecting rocks from seamounts (underwater volcanoes) that I can then break down and chemically analyze at UCSB. However, we are not in the dredging portion of the cruise yet, so I am going to attempt to walk you through the OBS recovery process from the perspective of someone who has never taken a geophysics class. Don’t worry, this post will be vetted by Zach (co-chief scientist) to make sure my descriptions are accurate! [Ed. note: Lindsay nailed it.]
Recovering an OBS is an interesting mix of extremely meticulous preparation and a hefty dollop of hope/faith that everything works exactly as planned. It requires seriously impressive engineering to have a sensitive electronic instrument remain functional for twelve months sitting 5 km deep in the Pacific Ocean. The attention to detail is total, even down to the sacrificial Zinc nodules which are attached strategically to prevent metal corrosion of steel components during their oceanic residency. Seawater will destroy almost anything over time (the ship is constantly being repainted to prevent it from rusting apart), but the OBSs emerge looking relatively fresh, and (for the most part) carrying one year’s worth of priceless data!
A freshly retrieved OBS. The gray lumps attract seawater ions that would otherwise corrode the instrument.
As Helen mentioned in her post, getting the OBS to rise requires that we “talk” to it. When the seismometers were deployed, they were told to “sleep” so that their batteries wouldn’t die before we could come back to collect them. When we are “on site” (within ~1 km of where we think the instrument is located on the ocean floor), we send a command for it to wake up so that it can talk to us. After we confirm its location, we send a “burn” command. This tells the OBS to detach itself from a weight (in this case a metal plate) that had been tethering it to the ocean floor. The OBSs are built so that they are naturally buoyant, and once they detach from the weight, they start to rise from the surface. The rise time varies between 1.5 and 2 hours, which gives us plenty of time to rock out to our ever-evolving burn playlist. Popular hits include Disco Inferno (the Trammps), Chariots of Fire (Vangelis), and Don’t You (Forget About Me) (Simple Minds). The last one is a bit off theme but it’s a favorite of our OBS technician Sean, and keeping him happy and dancing is a top priority.
Here Sean combines a demonstration of his dancing (to Frank Sinatra, this time) with perfect virtual tag line handling.
For those of you who haven’t thoroughly researched the R/V Roger Revelle’s nautical capabilities (hi, Dad), a very impressive feature of the ship is its ability to maintain its location within several meters, even during storms. This is incredibly useful, as once the OBS begins its journey to the surface, we have no control over its movements. Instead, we position ourselves ~300 m down-swell from where the OBS was located on the ocean floor and trust that the instrument will rise to the surface and float toward us.
An OBS at the surface.
It starts to feel a little like a rescue mission – the OBSs have these red flags that stick out above the water surface so we can spot them. Just before they are due to surface, the scientists all rush up to the 02 deck and engage in a friendly competition over who can spy the instrument first. Once they have been sighted, the ship slowly moves towards and alongside the OBS such that the instrument slowly passes very close to the starboard side of the deck. After roping in the OBS (with the help of a crane!), the OBS is then gently lowered onto the boat before being lovingly disassembled. A truly beautiful journey.
Lindsay Buff, UCSB, Token Petrologist
We use hooks at the end of long poles to affix ropes to the OBS to bring it aboard.Justin and Sean extracting the newly collected data.
This Thanksgiving Day, we’re trading in holiday parade floats for a (slower) parade of bright yellow OBS (Ocean Bottom Seismometer) floats. Since they’re made from syntactic foam, the latter do a lot better on the seafloor under 500 atmospheres of pressure. We are well into our recoveries and the 21 OBSs retrieved so far are starting to fill the deck.
The OBS we’ve recovered are being stored on the back deck and it’s fun to see them all next to each other. This float has the Pacific ORCA logo made on the first deployment cruise and signed by all science parties since.
Thanksgiving is near the halfway point of our cruise. Already we’ve learned so much, done lots of cool science, and seen many beautiful ocean views. I asked the science team to share a few things we’re grateful for about life at sea:
The food has definitely been a highlight, appearing on everyone’s thankful list. Joey is grateful for the unlimited candy supply in the mess (dining area); candy is an integral part of the #nightshift energy. Eva is thankful for “Potatoes, at least once a day, in glorious and myriad forms.” We’ve had them in all shapes (from hash browns to wedges) and textures (from mashed to baked). Best of all, they come bearing all sorts of wonderful salty flavors. The potatoes (and all the other food) cooked so expertly by Ruth and Mark (the ship’s stewards [i.e., the chefs]) have kept us all full and happy.
After a nice meal, sleep is the next thing on the agenda and Lindsay is grateful for the blackout curtains over the portholes and around the beds in our cabins. Waking up for his early morning shift, Brennan is thankful for discovering the ship’s tea stash, and is working his way through trying all the flavors to find his favorite. Waking up in the afternoon for the night shift, I am not only thankful for tea, but for the now-regular evening board games (especially Settlers of Catan) with new friends. Speaking of fun activities on the ship, Isabella is thankful for the two gyms on board and the morning yoga out on deck (when the seas are not being unreasonably rough).
Others are thankful for the little things. Zach appreciates that fact that he doesn’t have to change his trousers (much) while aboard and that the masks (worn diligently by all for the allotted two weeks) are off. Peter is thankful for all the laughter. Helen is grateful for “unexpected moments and beautiful views.” Lastly, Sean echoed everyone else’s first answer about what they were thankful for: their shipmates.
A flock of hand turkeys have appeared on the ship’s main hallway whiteboard, varying in occupation and artistic style, but all in the Thanksgiving spirit.The Captain tends to his smoker. Just the 25 knot winds at the time.
Thanksgiving Day itself has given us all much to be grateful for. The early hours of the morning and mid-afternoon have given us two more successful OBS recoveries. This morning many of us decided to make paper hand turkeys and a flock of them have been forming on the hallway whiteboard. And this afternoon I woke up to a wonderful Thanksgiving dinner. The Captain was literally up all night smoking two enormous turkeys on the 04 deck, rotating them regularly and dowsing the charcoal with a special citrus sauce hourly. This, and the “regular” roasted turkeys, paired well with mashed potatoes (Eva was very happy), stuffing, three kinds of pie, and fresh-from-the-oven rolls. Best of all was sharing the bounty with my awesome shipmates.
Happy Thanksgiving to you and yours from all of us here at 33° 40.204 S, 156° 2.701 W!
-Erica Nathan
Thanksgiving on the Roger Revelle, featuring my amazing shipmates Isabella, Sean, Lindsay, Eva, Peter, Helen, Zach, Andrew, Brennan, and Joey. Happy Thanksgiving!
Good Morning! It’s 1700 (5pm…) ship time, and the #nightshift is just rubbing its eyes awake. Connoisseurs of scientific cruise blogs may be familiar with the fact that operations on board take place 24/7. Now that we have completed our extended transit from San Diego to the experiment location in the South Pacific, all of the science party has switched over to our official shift schedules and recovery operations have begun. Mine is 2000-0800, so my day typically begins when I amble out to dinner, say my “G’mornings”, and eat some dinner for breakfast that inevitably sits strangely with the coffee I chug afterwards. I then wander downstairs to find the on-shift scientists, check where we are in our recovery schedule, and see what my shift is shaping up to look like for the night.
The benefits of the night shift include seeing both sunrises and sunsets, pictured here with a recently recovered OBS (photo c/o Erica Nathan).
This is my third time at sea, and second OBS recovery cruise. Each time, my appreciation for the variety of skills and expertise that combine to make this science happen increases. I think this is the first time I’m not feeling mostly overwhelmed by the experience. This is probably due to a mix of distilling information from my previous cruises, as well as our spending quite a bit longer on the ship than is typical before hectic recovery operations, due to COVID-related adjustments. The upside of the long transit was having much more time to actually learn about what we all do and why we’re here (even if we now need to relearn everyone’s faces with our masks off).
For this specific project, we’re in the remote Pacific Ocean to gather seismic data that will both help us learn about the processes related to tectonic movement of oceanic plates, as well as help fill in a gap in global seismic ray coverage in the Southern Hemisphere’s ocean basins. Addressing these scientific questions requires the use of seismic instruments that can operate on the deep seafloor – ocean bottom seismometers (OBSs). These OBS are the product of clever engineering (and maybe some wizardry); all of the scientific results and progress from this project owe a tremendous debt to the efforts of the people who build and maintain these instruments. We are also thankful for the crews of the R/V Kilo Moana (which deployed the array) and our current recovery platform, the R/V Roger Revelle. The crew have to put up with a bunch of us relatively inexperienced, non-mariner-type scientists for almost two months, so they deserve an extra round of applause.
Members of the science party on deck as we sail by Ua Huka in the Marquesas Islands. This was our first sight of land since setting sail from San Diego nearly two weeks prior.
Once we’re actually in Middle-of-Nowhere, Pacific Ocean, we still need to safely recover the OBSs back onto the ship. Once we are floating overhead, we “talk” to the instrument that has been on the seafloor for the past year. We (nicely) ask it to release its weights and float up to us. A couple of hours later (for the water depths we are working in), we start looking for its orange flag, big yellow body (housing the syntactic foam flotation), and strobe light on the surface. It also squawks to us loudly from a radio that the ship’s Bridge can pick up (and which annoys the heck out of them until we disable it post-recovery). It’s not my first time seeing an OBS bobbing around in the vast ocean at night, illuminated by the ship’s spotlight as we maneuver to bring it aboard, but the sight and the confluence of engineering and nautical skill encapsulated in that moment still leaves me staggered. The last push of the recovery requires quite a bit of dexterity in hooking lines to the instrument as it bobs up and down in the water alongside the ship, and then carefully using the “blue-crane” (painted gray, obviously) to haul it securely on deck. Then the geeky fun begins: we get seismic data off the instrument, evaluate the quality of the wiggles, and soon start answering scientific questions. The waveforms we collect will be the subjects of research for many scientists and graduate students over the next few years.
Our fearless techs wielding tag-line poles to hook an OBS as the ship is manoeuvered alongside.
I used data from these types of instruments for about eight years before I had the opportunity last year to sail to see this part of the process in action for the first time. It’s remarkable that the culture surrounding open data accessibility in seismology is such that anyone can actually access this data in a relatively short period of time – no seasickness, night shifts, and long trips away from home required! But it’s also an incredible privilege to be out here, on a floating OBS-centric microcosm with almost two months to spend teaching and learning from each other about our science and ranges of expertise. From my perspective, it’s an opportunity to think not only about the science that we do, but also how we do it and how we can continue to improve the process in the future.
On our way down to the recovery site, we had to take a jog southwards to avoid a storm path. Our new path put us, by chance, on a transect through the remote Marquesas Islands where –again by good luck– we passed the jagged volcanic island Ua Pou precisely in time for a stunning sunset, complete with dolphins in the water below us. Bluntly, it’s literally awe-some to think about all the random moments that contributed to me being aboard a cruise in the middle of a pandemic that let me see some of the most seldom-visited and beautiful islands in the world. Maybe some of the other science party and crew members feel similarly. To me, the experience fits with the idea of science itself sometimes being unexpected, shaped by random events, and hard to exactly plan. In a year where we are missing the normal random walk of conferences, meetings, visits to other institutions, and everything else that helps to fuel new research collaborations and ideas, the random path jogs with this group of shipmates have been a pretty special substitute.
Sunset over Ua Pou; dolphins not pictured (but they were really there!)
– Helen Janiszewski, co-Chief Scientist for the Old Pacific ORCA recovery cruise
I’m sure you’ve been wondering what the night life is like in the Pacific Ocean. So long as the clouds are cooperating, nights on board the Roger Revelle are for stargazing. Stargazing at sea is stargazing on challenge mode. Each night presents a noticeably (wonderfully) different sky, as we sail ~5° further south in latitude each day. We usually stay out long enough to watch the sky itself turn, with nothing above the horizon to diminish our view. If you want to follow along with the night sky I describe in this post virtually, you can plug our coordinates from a few nights ago (3° 36.021 S, 136° 40.362 W) into an online night sky viewer.
The purples of twilight in a clear sky are the prelude to a night of perfect stargazing.
After a spectacular sunset, we watch as the brighter colors fade to the pastel hues of twilight, eventually just a gradient of lavenders across the sky. The first night sky objects are already visible. Jupiter and its fainter companion, Saturn, shine high in the western sky. Across the ecliptic (the path through the sky that Sun, moon, and planets take across the sky), a bright red point of light is clearly identifiable as Mars. As the sky darkens further, brighter stars become visible- blue Vega in the northwest, in the constellation of Lyra, and Fomalhaut to our south swimming in the fishy constellation of Piscis Austrinus.
Once the last light from sunset has gone, the resulting night sky is resplendent. Far from any land, there is no light pollution except from our own ship. It is dark enough to make out the finer structure of the dark clouds in the Milky Way, cascading behind the bright constellation of Cygnus the Swan. In the southwestern skies, the darkness gives way to a bright diffuse triangle of light points up from the horizon; it’s the Zodiacal Light, sunlight scattering off interplanetary dust sitting just out of the plane of our solar system.
The motion of the boat makes it tricky to get pictures of the night sky, which require you to hold you camera still. This photo shows the stars ‘moving’ due to the motion of the boat when the camera is set on the deck and pointed straight up at the sky.
In keeping with our nautical setting, it is dark enough to make out all of the stars in the faint equatorial constellation Delphinus, so I’ll share a rather casual retelling of its constellation myth: In ancient Greece, there was a famous poet and singer called Arion. He was basically the ancient Greek version of a rockstar and he even went on tour. He sailed to different islands across the Mediterranean Sea, composing ballads and performing poetry. He left each tour stop with treasures and gifts given in appreciation of his talents. At the end of one of his long tours, he was sailing home to Corinth when the sailors on his ship decided they wanted Arion’s treasure for themselves and hatched a plot to toss Arion overboard and steal the treasure. Surrounded and about to be tossed into the sea, Arion pleaded that before the sailors drowned him that he could sing one last song. Knowing how talented he was and seeing no harm in this, the sailors agreed. Arion sang a song to Apollo (the Greek god of music) thanking Apollo for making him a rockstar. Hearing this, and noticing that Arion was a few verses away from certain death, Apollo asked Poseidon (the Greek god of the sea) to intervene. Poseidon sent a pod of dolphins to surround the boat, which leapt from wave to wave as Arion continued his song. Just as he was singing the last note of his song, Arion jumped overboard to escape the greedy sailors and the largest dolphin swam under him to rescue him from drowning. The dolphins carried Arion safely home and Apollo was so grateful for their intervention on behalf of his rockstar, that he honored that largest dolphin that saved Arion by placing it in the sky, to swim forever next to the Milky Way, listening to the music from the nearby constellation of Lyra.
On the observation deck, star stories are frequently interrupted by someone pointing to alert the rest of us to another shooting star, a passing satellite, or the sound of dolphins somewhere in the dark waves.
As it gets later, new constellations rise and before too long we are able to see both of the Magellanic Clouds, visible in only in the southern hemisphere. These two faint patches of light low in the southern sky are two irregular galaxies orbiting our own galaxy. They are hundreds of thousands of lightyears away and hold billions of stars. In addition to these new stellar wonders, I am also enjoying the opportunity to learn the southern hemisphere constellations. Some of my favorites that we’ve seen thus far include Grus (a bright constellation of a stork), Microscopium (a silly constellation of a microscope), and the Phoenix (a kite-shaped constellation).
The mast of the ship (right) is dimly illuminated in front of stars rotating around the south celestial pole. The two very faint bright clouds in the center and left of the image are the Small and Large Magellanic Clouds, respectively. At the horizon, barely visible real clouds darken the sky.
And though the night sky can easily occupy my attention for hours on end, I am frequently distracted by stunning displays of bioluminescence. Sometimes we see small, discrete flashes of bluish light alongside the ship- an imperfect mirror of the twinkling stars above. Another time, we saw large patches of greenish light cascading in a thunderstorm of light across the waves as far as we could see.
Helen, Isabella, and Eva (left to right) look down on the bioluminescence in the water below. Overhead, the familiar constellation of Orion sits low in the northeastern skies. The reddish star on the bottom left of Orion is Betelgeuse and the Orion Nebula is faintly visible to the right of the belt stars in this image.
From the skies to the seas, I am very much looking forward to seeing what surprises the night shift will hold during the rest of the journey. Wishing you clear skies and calm seas wherever you are.
Since we embarked on this voyage eleven days ago, a lot of things have been unexpected for me, a first-timer junior scientist at sea. However, there is one event in particular that has shocked me the most: The Equator crossing. I was born and raised in Brazil, so being in the southern hemisphere will always feel like at home. However, various things have been new to me. Crossing the Equator has brought along stories of crazy traditions, a different routine, new wildlife, amazing sunsets, and breathtaking night skies.
A happy flying fish showing its amazing wings. Photo by Erica Nathan.
As we were approaching the Equator, I started seeing groups of people laughing and planning to cut their hair, and I had no clue what was going on. After hearing the words “crawling” and “whale stomach” and “Neptune” I got curious and infiltrated some of these conversations. Turns out that, there are military naval customs and traditions that have been incorporated in other recreation boats that celebrate the “crossing the line”, when junior sailors, “Polliwogs”, are promoted to “Shellbacks”, in a context of an amusing story about King Neptune. These were originally effective leadership tools to install respect and sense of community among the sailors1. However, after reading about it and talking to people in the boat, today crossing the Equator has been an excuse to bond and have fun during long transits in the name of mysterious sea creatures. Activities revolve around ceremonies that are described metaphorically as “a rite of passage of baptism with ritual birth and rebirth, although it is also possible to find a crawl through a chute, mock trial and punishment, mythological pageant, and mock kidnapping and ransom as central rituals in the stage1.” More senior sailors have described their “baptism” while crossing the Equator with things involving shaving irregular parts of the hair and crawling on leftovers to simulate whale stomach. While these old stories are entertaining, for obvious reasons we didn’t evoke the spirit of king Neptune and didn’t do any sacrifice on his name.
Passing the equator was also a motivator to start a new routine. The weather suddenly changed and it has been steadily nice and warm. Some of us started doing yoga on the deck facing the ocean in the mornings, which has been very nice. The sound of the waves is so meditative that it makes me want to record it and make a playlist for myself when doing yoga in the cold winter back in Providence, RI, USA. The most fun of doing yoga outside is not the extra balance challenge and soothing waves sound… it’s the tan lines. Because we start off in a shady spot and we are enjoying being outside, we forget to put enough sunscreen and we’ve got the weirdest tan lines from our complex patterned leggings and the lovely face masks we need to wear to be safe against COVID.
Besides this, we have enjoyed eating outside during every meal, which is something I believe most of us missed since the start of the pandemic. Especially so because most of the time meals are followed by ice creams that come from our infinite stock of great flavors of Magnum and Hagen Daas (!!!) Unlike our time quarantining in San Diego, the birds here don’t steal our food from the balcony, which is nice.
Talking about birds, we have seen more marine life since we passed the 0˚ latitude. Birds start appearing more often as we get closer to the French Polynesia, and some of them are very interesting. Flying fish appear more often in different colors with their weird little wings, staying in mid-air long enough to get cool pictures of them. See above. During the day we have spotted manta rays and dolphins, and during the night, bioluminescent creatures we can’t describe. You will have to believe me that they are really amazing.
But even better than ranking and seeing day vs. night marine life are the sunsets at sea. When I first told some friends that had been in cruise ships I would be joining this expedition, they mentioned the sunsets and how incredible they are. I, very stubbornly, didn’t think they could be as beautiful as some other sunsets I’ve experienced around the world. However, the sunsets at sea are something. It is hard to describe. Zach, the PI came up with a Richter Scale style to rank sunsets awesomeness, where 3 is pretty common and 9 is very rare. All I will say is that you who is reading this should experience it at least once in your lives. We were extremely lucky to be passing some of the Marquesas Islands right at sunset one day after we passed the Equator, see photo below, and have passed other islands during the day since then. We are also lucky for what follows the sunset: a nice summer breeze and an amazing night sky.
Incredible sunset photo at the Marquesas islands. Photo is zoomed in – I wish we were this close to the islands. Photo by Erica Nathan.
Ah, the night sky at sea! In the southern hemisphere (which, we’ve now concluded, is the best hemisphere) has been showing beautiful and clear night skies that makes us forget everything that is going wrong (or right) with the world today. Constellations are seen so clearly, as well as the Milky Way, some satellites and many shooting starts. The sky’s beauty makes us want to be better scientists, teachers, and human beings. Beneath this immense dark space of sparkly dots, we share socially distant moments full of stories and lessons from ballet to Greek mythology, of course, always talking about seismology.
More details about the night sky are included in the next blog post! Stay tuned!
Atenciosamente,
Isabella Gama
1 Bronner, S. Crossing the Line Violence, Play, and Drama in Naval Equator Traditions. Amsterdam University Press, May 2020
Atravessando a linha do Equador
Desde que embarcamos nesta viagem onze dias atrás, muitas coisas foram inesperadas para mim, que sou uma cientista de primeira viagem no mar. No entanto, há um evento em particular que mais me chocou: a travessia do Equador. Eu nasci e cresci no Brasil, então estar no hemisfério sul sempre me fará sentir em casa. Entretanto, várias coisas foram novas para mim. Atravessar a linha do Equador foi um marco que trouxe histórias de tradições malucas, uma rotina diferente, uma nova vida selvagem, pores do sol incríveis e céus noturnos de tirar o fôlego.
Quando estávamos nos aproximando do Equador, comecei a ver grupos de pessoas rindo e planejando cortar o cabelo, e não tinha ideia do que estava acontecendo. Depois de ouvir as palavras “rastejando” e “estômago de baleia” e “Netuno” fiquei curioso e me infiltrou em algumas dessas conversas. Acontece que existem costumes e tradições navais militares que foram incorporadas em outros barcos de recreio que celebram a “passagem da linha”, quando os marinheiros juniores, “Polliwogs”, são promovidos a “Shellbacks”, no contexto de uma história divertida sobre o rei Netuno. Essas foram originalmente ferramentas de liderança eficazes para instalar respeito e senso de comunidade entre os marinheiros1. Porém, depois de ler sobre o assunto e conversar com as pessoas do barco, hoje a travessia do Equador foi uma desculpa para se unir e se divertir durante longos trânsitos em nome de misteriosas criaturas marinhas. As atividades giram em torno de cerimônias que são descritas metaforicamente como “um rito de passagem do batismo com nascimento e renascimento ritual, embora também seja possível encontrar um rastreamento por uma rampa, julgamento e punição simulados, desfile mitológico e sequestro e resgate simulados como centrais rituais no estágio1.” Marinheiros mais experientes descreveram seu “batismo” ao cruzar o Equador com coisas que envolvem raspar partes irregulares do cabelo e rastejar sobre as sobras de comida para simular o estômago de baleia. Embora essas velhas histórias sejam divertidas, por razões óbvias não evocamos o espírito do rei Netuno e não fizemos nenhum sacrifício em seu nome.
A ultrapassagem do equador também motivou o início de uma nova rotina. O tempo mudou repentinamente e tem estado continuamente agradável e quente. Alguns de nós começaram a fazer ioga no deck de frente para o mar pela manhã, o que tem sido muito bom. O som das ondas é tão meditativo que me dá vontade de gravá-lo e fazer uma playlist para mim mesmo ao fazer ioga no inverno frio em Providence, RI, EUA. O mais divertido de fazer ioga ao ar livre não é o desafio de equilíbrio extra e o som das ondas calmantes… é o bronzeamento irregular. Porque começamos em um local com sombra e estamos gostando de estar ao ar livre, esquecemos de colocar protetor solar suficiente e temos as mais estranhas linhas de bronzeado de nossas leggings estampadas complexas e as lindas máscaras faciais que precisamos usar para nos proteger contra COVID.
Além disso, gostamos de comer ao ar livre durante todas as refeições, algo que acredito que muitos de nós sentimos falta desde o início da pandemia. Especialmente porque na maioria das vezes as refeições são seguidas de sorvetes que vêm de nosso estoque infinito de ótimos sabores de Magnum e Hagen Daas (!!!) Ao contrário de nosso tempo de quarentena em San Diego, os pássaros aqui não roubam nossa comida de a varanda.
Por falar em pássaros, vimos mais vida marinha desde que passamos da latitude 0˚. Os pássaros começam a aparecer com mais frequência à medida que nos aproximamos da Polinésia Francesa, e alguns deles são muito interessantes. Os peixes voadores aparecem com mais frequência em cores diferentes com suas asinhas estranhas, permanecendo no ar por tempo suficiente para tirar fotos com bons ângulos, como mostrado na foto abaixo. Durante o dia, avistamos raias e golfinhos, e durante a noite, criaturas bioluminescentes que não podemos descrever. Você terá que acreditar em mim que eles são realmente incríveis.
Mas ainda melhor do que classificar e ver a vida marinha diurna vs. noturna são os pores do sol no mar. Quando contei pela primeira vez a alguns amigos que haviam estado em navios de cruzeiro que me juntaria a esta expedição, eles mencionaram o pôr do sol e como eles são incríveis. Eu, muito teimosamente, não achei que eles poderiam ser tão bonitos quanto alguns outros pores do sol que já experienciei ao redor do mundo. No entanto, o pôr do sol no mar é alguma coisa. É difícil de descrever. Zach, o PI veio com um estilo de Escala Richter para classificar o pôr do sol como algo incrível, onde 3 é bastante comum e 9 é muito raro. Tudo o que direi é que vocês que estão lendo isso devem experimentar pelo menos uma vez na vida. Tivemos muita sorte em passar por algumas das Ilhas Marquesas logo ao pôr do sol um dia depois de passarmos o Equador, veja a foto abaixo, e ter passado por outras ilhas durante o dia desde então. Também temos sorte pelo que se segue ao pôr do sol: uma agradável brisa de verão e um céu noturno incrível.
Ah, o céu noturno no mar! O hemisfério sul (que, agora concluímos, é o melhor hemisfério) tem mostrado um céu noturno lindo e claro que nos faz esquecer tudo o que está dando errado (ou certo) no mundo hoje. As constelações são vistas tão claramente, assim como a Via Láctea, alguns satélites e muitas estrelas cadentes. A beleza do céu nos faz querer ser melhores cientistas, professores e seres humanos. Debaixo desse imenso espaço escuro de pontos brilhantes, compartilhamos momentos socialmente distantes cheios de histórias e lições do balé à mitologia grega, é claro, sempre falando sobre sismologia.
Cheers,
Isabella Gama
1 Bronner, S. Crossing the Line Violence, Play, and Drama in Naval Equator Traditions. Amsterdam University Press, May 2020
Hello Old ORCA fans. I’m Brennan, a UCSB PhD student volunteering for this project. We are now on our 10th day on board the R/V Roger Revelle. As is the case for many of the scientists on board, this approximately 50-day voyage is my first time at sea. I’ll briefly describe a selection of experiences I’ve had which I hope will paint a small portion of a picture of what sailing the seas for science is like.
Yours truly, on the back deck.
Our main goal is to recovery ocean bottom seismometers. Lying in bed at night, the swaying of the boat every ~10 seconds in response to ocean waves provides a similar feeling to what an ocean bottom seismometer must experience. The seismology master Charles Richter once said (lightly paraphrasing) “to become a true seismologist, you must be one with the seismometer.” Similarly, eastern philosophies teach that one cannot simultaneously know and speak. We must be as a seismometer and listen.
There are some key rules of which I’ll briefly mention a few. We must wear masks, maintain physical distance from each other, and wash hands frequently. I thought this was excessive at first, since I’ve found that both the scientists and sailors seem to be rather fine people. Evidently, this is instead a COVID precaution. In all seriousness, after sailing away from land for over a week, the prospect of any individual on board needing hospitalization for COVID treatment is not particularly pleasing. I can report that there has been an immense effort to prevent this from occurring, from the two-week quarantine in a hotel at Shelter Island in San Diego, to continued social distancing onboard for over two weeks.
The constant flow of coffee has been a lovely perk. Aside from avoiding falling off the boat, perhaps the rule which I am most afraid to break is: thou shalt keep coffee in the coffee pot. While refilling the pot recently, the massive empty container of ground coffee indicated the extent of the crew’s coffee obsession. Thus, I had my first experience grinding coffee beans. My inexperience with grinding fresh beans was hard to mask when pale yellow/brown liquid, a highly diluted and sad excuse for coffee, began draining from the filter into one of the communal pots. Unaware of a way to turn the coffee maker off, I fled the scene to avoid the wrath of undercaffeinated coffee drinkers.
Safety is taken very seriously, so we practiced putting on immersion suits which are designed to prevent a person in water from getting hypothermia. In practice, this translates to wearing lobster costumes. They are as difficult to put on as they are entertaining to look at.
We have been spoiled by two chefs who deliver heaping plates of excellent food for each meal. But the most astonishing thing is that the fruit which the cooks keep serving has not gone bad. Since experiences in my own kitchen suggest that perfectly ripe fruit is a rather ephemeral substance, and I have not seen land or another vessel for a week, I’m forced to conclude that mid-ocean fruit trees, although highly elusive, exist. I remain vigilant in hope of seeing one. I’m optimistic that over the remaining 40 days at sea, these efforts will pay off with a bonus whale sighting.
This pose absolutely screams “equator crossing”
We crossed the equator this morning. The equator line drawn on globes is a bit of an exaggeration as not even the most imaginative of us were able to see it. We celebrated with a nice brief afternoon lollygagging which consisted of a few (100% voluntary) haircuts. All I will say about that is the difference in skill between our two volunteer barbers quickly became clear.
Behind the boat, we tow fishing lines and a magnetometer. The magnetometer measures the strength of the magnetic field which is influenced by iron bearing minerals in the sea floor. These record how the Earth’s magnetic field has changed through time. The fishing lines are similarly not just for show: so far, the crew caught two fish over about four feet long. I can only guess that this is an effort to minimize the cost of feeding the dozens of hungry people on board.
We look forward to returning home with a new wealth of data.
Thanks for reading, Brennan
One of many beautiful sunsets we have now enjoyed.
Pacific ORCA 