Science communication is an often overlooked aspect of science, with most scientists focusing on the research rather than sharing their findings. When they do share it, it is often coded in difficult-to-understand jargon which limits who can understand what is being explained to them. This is not good. What is the purpose of doing science if what you are discovering is not accessible to be shared with others?
The main problem when it comes to science communication is that most scientists will act as their mentors when it comes to teaching and leading. This is not necessarily a bad thing if their predecessors were focused on being good science communicators, but if they were shown to “gatekeep” and only share with those who they think are useful there is a high chance that they will not be the best science communicators. Thankfully I have been able to be mentored by great science communicators who make it a priority to share not only their science but that of their colleagues as well.
This semester I had the privilege of taking Dr. Adriane Lam’s science communication course, where I have been able to learn how to be a better scientist, not just in the lab but in the real world. Her class gave me more insight into how to talk to my friends and family about what I do for research and the importance of it. Talking with the guest lecturers, like Dr. Sarah Sheffield, opened my eyes to the importance of science communication by giving me more insight into how just by changing your language and tone, you can communicate science to those who are a little bit more reluctant to listen. Before, I felt it was too difficult to explain what I do because it is not “revolutionary” and geology is not always seen as a primary science, meaning it is a bit unknown to the general public. So explaining glacier mechanics did not seem like the best use of time but now I will try to take caution when explaining my work by using easier-to-understand language and when met with resistance to change my tone so that my work comes across as more understandable.
This post was written by Halima Ibrahim, a graduate student at Binghamton University in the seminar Science Communication for Scientific Ocean Drilling (SciComm for SciOD), Spring 2023.
Throughout this course, I have had the privilege to explore and reflect on various concepts and ideas related to science communication. One of the key takeaways for me has been the vital role of effective communication in conveying scientific ideas and findings to a broader audience. Through this class, I have learned about the best practices in science communication and the various strategies and techniques that can be used to engage with diverse audiences.
The class discussions on the science communication book, “Getting to the heart of science communication: A guide to effective engagement” by Faith Kearns, were particularly fascinating. The author did an excellent job of sharing her career experiences and challenges as well as other science communicators in communicating science to the general public. The book also highlighted the need for scientists and researchers to be transparent and clear in their communication with both scientific and non-scientific communities. Our discussions over each chapter of the book were enriching, as they provided me with different perspectives and opinions from other people’s points of view.
I also appreciated the opportunity to listen to the five invited speakers who shared their research work, experiences, and how they communicate their science to a broad range of people, from the classroom to the general public. Most of the speakers had an extensive background in scientific ocean drilling, which is the area of my research interest. Some of them were involved in outreach programs to communicate science to non-experts as well as the younger generation, which was insightful to learn about their achievements. The peer review process was another aspect of the class that I enjoyed. Reviewing another person’s webpage and providing constructive feedback was fun, and it presented an opportunity to learn about other expeditions.
One of the reasons I took this class was to improve my science communication skills and contribute to the advancement of scientific knowledge through creating web pages of past International Ocean Discovery Program (IODP) Expeditions on the Time Scavengers website. These web pages will eventually be consumed by the Flyover Country app. It is fulfilling and humbling to know that someone may find the write-up that I produced in this class useful at some point in their life. The knowledge and skills I have gained from this class will enable me to effectively communicate scientific ideas in the future. I plan to apply these learnings to communicate scientific concepts and research findings more clearly and transparently to both scientific and non-scientific audiences. Furthermore, I intend to engage with different science communication strategies and seek feedback from various audiences to improve the effectiveness of my communication skills.
I appreciate Dr. Adriane Lam, our instructor, for doing an excellent job, especially as it was her first time teaching the class. From curating the course outline and choosing the book for the class to carefully selecting the invited speakers who had a wealth of knowledge to share with the class, she was amazing. I particularly liked the engaging and hands-on nature of the class. Dr. Lam is an excellent science communicator, which was evident in how she made in-class communication a two-way process by transmitting information to us students and receiving our feedback and opinions. The in-class exercises were helpful, and Dr. Lam was readily available to guide us and answer all our questions.
In conclusion, this class has been immensely valuable in enhancing my knowledge and understanding of science communication. I feel much more confident and better equipped to effectively communicate my research to people who do not have a scientific background. I have also come to appreciate the role science communication plays in shaping public opinion and understanding of complex scientific concepts such as climate change, oceanic drilling programs, and various scientific policies. I highly recommend this course to anyone interested in science communication, be it to learn how to communicate their scientific knowledge to folks from different knowledge backgrounds or to venture into a science communication career.
This post was written by Yiran Li, a graduate student at Binghamton University in the seminar Science Communication for Scientific Ocean Drilling (SciComm for SciOD), Spring 2023.
For me, one of the key takeaways from graduate school was learning that being able to effectively communicate and share your research with others is just as important as the research itself, and that it is a crucial skill for integrating oneself into a collaborative research environment such as the one we have in the geosciences community. Participating in the SciComm seminar was an eye-opening experience for me. As a student of observational seismology, I had a general idea of what the International Ocean Discovery Program is through course works, but was completely unfamiliar with the aspect of community culture that advocates and invests in mentorship opportunities.
Many topics explored in this course were very new to me. It was really interesting to hear about journal studies that evaluate the effectiveness of different pathways in scientific communications, whether that’s interactions on social media or through outreach programs. I also empathized with the experiences of students who are just starting out in earth sciences, and how they discovered a community by participating in research opportunities – I had no idea that these literatures existed, and really appreciated the fact that there are published works highlighting the emotional aspects of pursuing careers in geoscience research. It helped me reflect over my own experiences as well. I hope to get more involved, and further explore more opportunities in science communication in the future.
Hello! My name is Alex Corsello and I recently graduated from Binghamton University studying Biology and Earth Science. I’m originally from Virginia, but grew up in Katonah NY, about an hour from New York City (yes there are dirt roads). Additionally, I will be staying at Binghamton to pursue my Masters of Arts in Teaching Earth Science. I am a big fan of hiking, running and baking. While not in the lab I have visited over 100 national parks across the United States, ranging from Yosemite to a tiny house on the corner of a street in Philadelphia.
I am a paleontologist who studies foraminifera, or forams for short, particularly within the Miocene Period (roughly between 5 and 23 million years ago). My research specifically focuses on determining two things. First, where does the foram species Globoquadrina dehiscens live in the water column in a mid-latitude site? Second, can G.dehiscens be used as an indicator for past ocean temperatures conditions? Samples are taken from cores drilled through the International Ocean Discovery Program, washed and then picked by size for the particular species that I am studying. Then, using the shell of the organism my samples are sent to Hamilton College, where they are analyzed for both oxygen and carbon isotopes. These isotopic ratios help to provide a picture of the temperature of the water where the organism lived and how productivity there was in the region where this was taking place. Thus it becomes possible to reconstruct ocean conditions. The goal of our lab is to help determine how ocean conditions changed in response to various climate variables in the past in order to best predict how they might change again under a warming climate.
Alex and a class of second graders at Finn Academy in Elmira, NY, where he conducted an outreach program with the students.
I have always been a bit of a nature nerd… I went to ecology camp starting in first grade. But growing up I always thought I would be a historian. This changed when I took Biology in high school and I became fascinated with how life works. Every part of life, even if it seems really distant, is connected in some way and I think that’s really cool. I started as a Biology major and after taking my first geology class as part of my Biology degree I was hooked. I have been working on earth science research ever since. My favorite part of science is getting to tackle real world problems and to try to make a positive difference for others through your work. You never know what idea could be the key to a big discovery or the tool that solves a pressing problem. There is also something incredibly magical about getting people interested in science. The excitement that comes with learning is infectious and watching those who may have previously been adverse to science start to connect is really powerful.
Alex presenting his research in poster format the Joint Southeastern/Northeastern Geological Society of America meeting in Reston, VA.
Take risks- That seemingly crazy idea that you came up with while on the toilet at 3 am may help define your path. A lot of the time, yeah, you’ll fail. But it is those few experiences where you succeed that can help to define your path both as a scientist and human being. They are what lead to more opportunities and a whole host of new people and places. Also don’t be afraid to use your resources. There are people who are in your corner who will be there to advocate for you. Don’t be afraid to get their help. You will be much better off for it.
This post was written by Charlotte Heo, a graduate student at Binghamton University in the seminar Science Communication for Scientific Ocean Drilling (SciComm for SciOD), Spring 2023.
Here’s a picture of me presenting my research at the spring 2023 regional Southeastern/Northeastern Geological Society of America conference and it’s an example of what I think of when I imagine science communication but casually talking about research at the dinner table with family and friends can also be considered science communication as well!
I decided to take SciCommSciOD this semester because I had some free time in my schedule and I wanted to show my support for a new class. I am so glad I decided to because I have learned so much about science communication that I was not aware about before. Science communication is a growing area of interest in the scientific community and I definitely think it should be talked about more and prior to the formation of this class my university lacked a curriculum like it. SciCommSciOD opened me up to new perspectives about sharing science, such as how science communication can be used as a tool to connect with people directly affected by science and it shifted my perspective to think more about the people I want to share my science with. I think sometimes I struggle with SciComm because a lot of the time I’m sharing my science with people with strictly science backgrounds such as at conferences or seminars but it is really important for me to make my research accessible to the public. The work that I do directly pertains to climate change which impacts a ton of different people within different communities and backgrounds (both in science and in public audiences) so it’s necessary to be able to have a discussion about it in an accessible way. Overall, I hope that learning about science communication becomes more of a standard in the scientific community, and as scientists I believe we have a responsibility to effectively communicate our findings in accessible ways.
Map of locations for sites that were drilled during Leg 329 on the South Pacific Gyre off of the coast of New Zealand. Figure from IODP Expedition 329 Summary.
International Ocean Drilling Program (IODP) Expedition 329 took place from October to December in 2010 and drilled Sites U1365–U1371 in the South Pacific Gyre, a large system of rotating ocean currents in the South Pacific Ocean located off the coast of New Zealand. The expedition was a collaboration between scientists and staff from the United States, Japan, Germany, China, Norway, the United Kingdom, New Zealand, Korea, Australia, and India. Currently, there are no other ocean drilling sites located near Expedition 329 sites making it a massively understudied location. The sites drilled and studied during this expedition are an excellent location for exploring and researching subseafloor sedimentary habitats in what is considered to be the center of an open ocean gyre. The South Pacific Gyre is Earth’s largest gyre system out of five total gyre systems. Even though the cores recovered on Expedition 329 vary in ages, they are all extremely useful in understanding hydrothermal circulation (the circulation of hot water), and habitability (the capacity to be lived in) of oceanic crusts.
Detailed image of a calcite crystal contained within a section of basalt, the rock that makes up the ocean crust. Blue coloring is from a marker. Image from the LIMS Database.
Expedition 329 had four major objectives: 1) to document habitats; 2) research how oceanographic factors affect habitats; 3) quantify subseafloor microbial communities; and 4) determine how habitats at the sites vary with crust age. Before Expedition 329, life in the sediments beneath mid-ocean gyres was generally understudied and poorly understood, despite the South Pacific Gyre being a unique location. Within this gyre system, surface chlorophyll concentrations and primary photosynthetic productivity in the seawater are lower than in other ocean regions, contributing to some of the lowest organic burial rates in the ocean. Scientists and staff aboard the ship during this expedition found that microbial cell counts are lower than at all sites previously drilled, dissolved oxygen and nitrate are present throughout the entire sediment sequence, and dissolved hydrogen concentration is low but often above detection limits in deeper sediments. High-resolution chemical and physical measurements provided the opportunity for reconstructing glacial seawater characteristics through the South Pacific Gyre. Overall, Expedition 329’s findings and discoveries of the presence of dissolved chemicals revealed that there is microbial habitability of the entire sediment sequence, offering valuable insights into gyre habitability.
References
D’Hondt, S.L., Jørgensen, B.B., Miller, D.J., et al., 2003. Proc. ODP, Init. Repts., 201: College Station, TX (Ocean Drilling Program). doi:10.2973/odp.proc.ir.201.2003
Dubois, N., Mitchell, N. C., & Hall, I. R. (2014, April). Data report: particle size distribution for IODP Expedition 329 sites in the South Pacific Gyre. In Proc. IODP| Volume (Vol. 329, p. 2).
Expedition 329 Scientists, 2011. Methods. In D’Hondt, S., Inagaki, F., Alvarez Zarikian, C.A., and the Expedition 329 Scientists, Proc. IODP, 329: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.329.102.2011
Figure 1. Map of the arctic ocean showing the locations of the EXP 302 study area on the Lomonosov Ridge. The small-scale map shows the locations of EXP 302 sites. Figure from IODP Expedition 302 Summary.
In 2004, The Integrated Ocean Discovery Program (IODP), completed its three-hundred-and-second expedition located in the central Arctic Ocean at Lomonosov Ridge, about 250 km from the North Pole (Figure 1). During this expedition, the scientists and crew were able to recover sediment cores from three (M0002—M0004) out of the four holes they drilled (Figure 2F). The recovered sediment core depth was up to 428 meters below the seafloor. The main objective for this expedition was to further study the ancient ocean currents and ocean behavior (paleoceanography) of the Arctic region, specifically to better understand the past climate of the central Arctic Ocean and its impact during the Cenozoic Era (66 million years ago to today), when the Earth changed from a “Greenhouse” world (a time when there is very little to no ice on Earth) in the Eocene (~41 million years ago) to an “Icehouse” world (a time when there is extensive ice) of today.
During Expedition 302, the primary objective was to continuously recover sediment records (cores) and to sample the underlying bedrock by drilling and coring from the stationary drillship. This was not an easy task because of the prominent moving heavy sea ice at the Lomonosov Ridge. In order to prevent the ice from complicating the mission, a fleet of 3 icebreaker ships were used: The drilling vessel the Vidar Viking, a nuclear Russian icebreaker Sovetskiy Soyuz, and a diesel-electric icebreaker Oden. The primary goal of the icebreakers was to protect the drilling ship to ensure smooth drilling and coring operations.
Figure 2. Seismic reflection profile of the Lomonosov Ridge (AWI-91090) with locations of Expedition 302 coring sites. Multichannel seismic data are from Jokat et al. (1992). Cores were not retrieved from Hole M0001A because the BHA (gray on figure) was lost. Hole M0004B is located ~60 m away from Hole M0004A; Hole M0004C is located ~60 m away from Hole M0004B. SP = shotpoint. Image from IODP Expedition 302 Summary.
The scientific objectives of Expedition 302 are split between paleoceanography (reconstructing ancient ocean conditions) and tectonics.
The paleoceanographic objectives included:
Determining the history of sea ice and ice rafting in the region
Studying the differences between local and regional ice development
Determining the density structure (related to temperature and salinity) of the Arctic Ocean surface waters
Determining the timing and consequences of the opening of the Bering Strait
Studying the land-sea links and the response of the Arctic to the Pliocene (~5.3–2.58 million years ago) warming events
Investigating the development of the Fram Strait and deepwater exchange between the Arctic Ocean and Greenland/Iceland/Norwegian Sea (Figure 3)
Determine the history of biogenic sedimentation (sediments made by organisms).
The tectonic objectives included:
Investigating the nature and origin of the Lomonosov Ridge by sampling the oldest rocks below the regional unconformity (a time when there are no sediments that represent a specific time interval in the sediment and rock record) in order to establish the pre-Cenozoic environmental setting of the ridge
Studying the history of rifting and the timing of tectonic events that affected the ridge.
Figure 3. Generalized schematic of sea ice transport in the Arctic Ocean. Red contours denote average years of residence time before sea ice export through the Fram Strait. Arrows indicate average transport speeds. Figure from IODP Expedition 302 Summary.
IODP Exp. 302 was the first ever drilling project that was able to drill in this location, making the results pretty revolutionary. Not only were they able to gain information on all of their objectives, they also gained information on the Paleocene/Eocene Thermal Maximum (PETM; ~55.5 million years ago). This boundary was recovered during the drilling and it represents a time when the temperature of the Arctic Ocean waters exceeded 20°C or 68°F. The efforts put into this expedition made great advancements in science since this is the most cited IODP cruise!
The sites drilled as part of IODP Expedition 363 in the western Pacific warm pool region of the western equatorial Pacific ocean. Sites are denoted by yellow dots. Figure from IODP 363 Summary.
El-Niño is a phenomenon that occurs in the equatorial Pacific Ocean, causing a short-term shift in global weather dynamics around the world. El-Niño involves weakening of the trade winds, which usually push warm surface waters from the eastern equatorial Pacific to the western equatorial Pacific. Such weakening of the trade winds leads to warmer waters to occur in the eastern equatorial Pacific, when there is usually a ‘tongue’ of cold water at the surface ocean in this region. The rate of change in ocean temperatures, which is the driver of much of the global weather effects associated with El-Niño, have changed alongside global climate dynamics. Every few years, the wind patterns across the equatorial Pacific change, sometimes also shifting to a La Niña phase. The La Niña phase includes strengthening of the trade winds, which leads to even more warm water piling up in the western equatorial Pacific, and cooler waters to appear in the eastern equatorial Pacific. Preliminary studies show that the amount of time between La-Niña and El-Niño conditions are shifting over geologic time. A separate process affected by ocean surface water temperatures in the southeastern Asia region are the Australian Monsoons. These monsoons come off the Indian Ocean and provide rainfall to a significant portion of the northwestern Australian continent. There are two seasons in monsoon climates, a rainy season where moisture laden air moves over land, and a dry season where dry air moves over the oceans. Figuring out how both global and local processes based in the southeast Pacific are affected by warming oceanic conditions will play a large role in understanding climate change in the future.
The El-Niño Southern Oscillation pattern in the Pacific Ocean versus the Pacific Ocean in a year under normal conditions.
The best way to study how the climate system interacts with El-Niño conditions is to look at the past. A prime example is the Middle Miocene, a time period of warming occurring 15 million years ago. The warming patterns of the Middle Miocene are similar to warming trends that are seen today, and thus represent a clear example of how carbon dioxide (a greenhouse gas) changes in the atmosphere can influence global sea surface trends.
Expedition 363 took advantage of the geologic record of sediments in the western equatorial Pacific to reconstruct the La Niña and El Niño phases of the geologic past. The goal of Expedition 363 was to determine how different climate variables changed in the Western Pacific Warm Pool, the pile of warm water in the western equatorial Pacific. Of particular importance was to determine how these changes related to global climate change through the mid-Miocene to the mid-Pleistocene (~15 to 3 million years ago). More specifically, the expedition wanted to determine how shorter scale climate variability across a millennium. Particularly the study looked at the balance between El-Niño and La- Niña conditions, which can be correlated to previously obtained data on climate and greenhouse gas emissions. Additionally this expedition focused on understanding the history and variables that affect the Australian Monsoon cycle.
An illustration of La Niña Conditions over the eastern to western equatorial Pacific Ocean. During La Nina conditions, the trade winds strengthen, pushing warm surface waters from the eastern equatorial Pacific to the western equatorial Pacific. Figure from the National Oceanic and Atmospheric Administration.
Sediments recovered during Expedition 363 will allow for a better understanding of the Middle to Late Miocene Periods. Additionally it will allow for a better understanding of the Australian Monsoon system. Geochemical analyses from this site shows that mixed layer surface ocean temperatures did not cool over time, while subocean temperatures cooled significantly suggesting a change to more overall La-Niña conditions over time. Additionally, maximum greenhouse gas emissions coupled with peak insolation for the Southern Hemisphere provided the shortest Australian Monsoon season. Thus future predictions in a world with increased carbon dioxide levels and warming, would suggest that given rising global temperature a shorter monsoon season would occur.
References
Rosenthal, A.E. Holbourn, D.K. Kulhanek, I.W. Aiello, T.L. Babila, G. Bayon, L. Beaufort, S.C. Bova, J.-H. Chun, H. Dang, A.J. Drury, T. Dunkley Jones, P.P.B. Eichler, A.G. Fernando, K. Gibson, R.G. Hatfield, D.L. Johnson, Y. Kumagai, T. Li, B.K. Linsley, N. Meinicke, G.S. Mountain, B.N. Opdyke, P.N. Pearson, C.R. Poole, A.C. Ravelo, T. Sagawa, A. Schmitt, J.B. Wurtzel, J. Xu, M. Yamamoto, and Y.G. Zhang. (n.d.). Expedition 363 summary. https://doi.org/10.14379/iodp.proc.363.101.2018
Pei, R., Kuhnt, W., Holbourn, A., Hingst, J., Koppe, M., Schultz, J., Kopetz, P., Zhang, P., & Andersen, N. (2021). Monitoring Australian Monsoon variability over the past four glacial cycles. Palaeogeography, Palaeoclimatology, Palaeoecology, 568, 110280. https://doi.org/10.1016/j.palaeo.2021.110280
Steinthorsdottir, M., Coxall, H. K., De Boer, A. M., Huber, M., Barbolini, N., Bradshaw, C. D., Burls, N. J., Feakins, S. J., Gasson, E., Henderiks, J., Holbourn, A. E., Kiel, S., Kohn, M. J., Knorr, G., Kürschner, W. M., Lear, C. H., Liebrand, D., Lunt, D. J., Mörs, T., … Strömberg, C. A. E. (2021). The miocene: The future of the past. Paleoceanography and Paleoclimatology, 36(4). https://doi.org/10.1029/2020PA004037
Microfossils that were contained within the sediments retrieved during Expedition 363. The chemistry of these fossils’ shells, or tests, can be used to reconstruct ancient ocean conditions. Image from the LIMS database.
Figure 1: A schematics of proposed slip style and stability around different parts of a megathrust system (Yao et al., 2017).
The great Tohoku earthquake that struck northeastern Japan in 2011 was one of the largest earthquakes ever recorded on the Earth. The 9.1 magnitude earthquake resulted in a devastatingly shaking tsunami that not only produced large death tolls and structural damages but also revealed that our understanding of how the large subduction zone faults behave needs to improve in order to better predict and mitigate future earthquakes. Integrated Ocean Drilling Program Expedition 343 drilled down to the slip interface near the earthquake epicenter in offshore Japan subduction zone with the aim of recovering both geophysical data and material samples around the fault surface (Figure 2). Geoscientists used these data to form a detailed understanding of what is happening to the earth material around the fault when large ruptures occur, incorporating many parameters like states of temperature and stress, sediment type, pre-existing fault structure, and fluid flow (Chester et al., 2013)
Figure 2: Drill sites around the Tohoku-oki earthquake epicenter in offshore eastern Japan. Core samples were collected from ~5 km inland from the trench, sampling the toe of the sedimentary accretionary prisms closest to the subduction zone down to the depth of ~840 m (Chester et al., 2013).
Megathrusts along subduction zones produce the largest earthquakes on the Earth due to the long fault length and relatively wide slip surfaces. The fault rupture associated with the 2011 earthquake reached over 62 m in slip along a 40 km long segment of the Japan Trench (Sun et al., 2017). The slip was considered unusually large for an event that took place at shallow depths in the Earth near the subduction trench, where the fault surface was generally believed to be stable (Figure 1, Yao et al., 2013). While the occurrence is less frequent, shallow rupture events of this magnitude need to be monitored because the slip can breach and significantly displace the seafloor, which will cause tsunamis.
The deepest points in the Earth’s ocean are subduction trenches, where the downgoing oceanic plate bends and sinks beneath the overriding continental plate (Figure 1). The JFAST project reached one of the deepest water depths amongst all of the expeditions in the International Ocean Discovery Program (IODP Expedition Statistics) in order to tap into the shallowest portion of the subduction megathrust. In total, five boreholes were attempted at Site C0019 (Figure 2), three of which successfully reached the target fault surface (Chester et al., 2013). Multiple types of data were carefully collected over the course of a month. In addition to successfully recovering the cores, the expedition also performed real time well logging while drilling (LWD) to retrieve in situ conditions of the sediment and materials surrounding the fault surface. High-resolution electrical images also illuminated the structures and lithological properties in the borehole and enabled the identification of plate boundary fault zones (Figure 3, top). In particular, the patterns of the beddings and fractures inferred from the borehole images showed multiple faults that comprise the fault zone and drastic change in sediment structures as they are sheared by plate motion (Figure 3, bottom). Finally, temperature sensors were directly deployed along the fault interface in Hole C0019D during expedition 343T to measure the remaining frictional heat produced from the slip event 16 months prior (Figure 4).
Figure 3: The fault zone was reached at ~720 m below the sea surface (Chester et al., 2013). (top) borehole images and well logs taken along the fault zone and (bottom) combined interpretation of bedding structures near the fault zone (Chester et al., 2013).
References
Expedition 343/343T Scientists (2013). Site C0019. In Chester, F.M., Mori, J., Eguchi, N., Toczko, S., and the Expedition 343/343T Scientists, Proc. IODP, 343/343T: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.343343T.103.2013
Sun, T., Wang, K., Fujiwara, T., Kodaira, S., & He, J. (2017). Large fault slip peaking at trench in the 2011 Tohoku-oki earthquake. Nature communications, 8(1), 14044.
Yao, H., Shearer, P. M., & Gerstoft, P. (2013). Compressive sensing of frequency-dependent seismic radiation from subduction zone megathrust ruptures. Proceedings of the National Academy of Sciences, 110(12), 4512-4517.
Figure 4: Borehole opening at the seabed (6897.5 m deep!), where the tubing pipe of the temperature observatory is being lowered down and installed along the fault zone to measure frictional heat released from the Tohoku earthquake (Photo galleries, JAMSTEC).
Figure 1. The location of New Zealand with respect to the complex tectonic boundaries between the the Pacific plate and the Australian plate (Barnes et al., 2019). Cooler, darker colors represent deeper areas of the ocean, whereas warmer colors represent shallower regions around New Zealand.
New Zealand is tectonically complex, hosting both subduction and strike-slip fault zones associated with the plate boundary between the Pacific plate and the Australian plate. The country is thus geologically active, with many potential natural hazards that require investigation and close monitoring (Figure 1, Barnes et al., 2019). The need for improved mitigation also presents an opportunity to better understand the Earth processes prevalent in active tectonic settings. Between 2017–2018, International Ocean Discovery Program Expeditions 372 and 375 set out to collect data (cores, well logs, and in-situ geophysical measurements) at the Hikurangi Margin in northern New Zealand, with primary goals of better understanding the mechanisms and behaviors of gas hydrate-bearing landslide (Barnes et al., 2019) and slow slip events on subduction faults (Saffer et al., 2019). A combined total of six sites were sampled between the two expeditions, with two in the Tuaheni Landslide Complex (TLC) and four in a transect across the Kermadec Trench near the Hikurangi Margin.
Submarine landslides are often the byproduct of catastrophic destabilization events like earthquakes. If severe, the resulting slope failure can sometimes significantly displace the seafloor, even causing tsunamis (Harbitz et al., 2014). However, the submarine Tuaheni Landslide Complex in the offshore Hikurangi margin is unusual, showing evidence of slow, continuous downslope movement of sediment rather than discrete events. Furthermore, the onset of landslides seem to correlate with the edge of gas-hydrate, with a general shift in the styles of seafloor deformation above and below the depths where the gas hydrates are stable (Figure 2, Mountjoy et al., 2014). The cores and well logs collected from Expedition 372 were used to test several hypotheses on how exactly the gas hydrates are related to the observed gradual landslides.
Figure 2. A seismic subsurface image (Mountjoy et al., 2014) showing the cross section of submarine landslides at the Tuaheni Landslide Complex. The lateral change in deformation style across the locations of gas hydrates (strong amplitude in the seismic section) can be inferred from the different faulting style.
Hikurangi Margin is also well documented for another tectonic phenomenon that is observed along the subduction zones, called slow slip events (SSEs). Unlike the devastating megathrust ruptures that release strong seismic energy from sudden movements along the fault surface, SSEs release energy gradually, over a course of weeks or even months (Saffer et al., 2019). While not necessarily an immediate natural hazard, the phenomenon is a relatively recent finding and garnered increased attention from the research community in the last two decades as the observational techniques improved and densified. Hikurangi margin hosts a region of well-studied SSEs with regular occurrences, where the fault (Pāpaku fault) is at shallow depths, accessible by drilling (Saffer et al., 2019). The goal of Expedition 375 was to reach and sample the fault zone, through coring, wireline logging, and installment of geophysical observatories (Figure 3).
Figure 3. An interpreted seismic subsurface image (Barker et al., 2019) of the drill location relative to the Papaku fault.
Recent studies have begun to shed light on the mechanisms behind the above phenomena using the core and geophysical data retrieved by Expeditions 372 and 375. For example, the cores from Expedition 375 reveal highly variable lithologies near the slow slip fault surface, ranging from marine clay and carbonates to volcaniclastic and conglomerate rocks (Figure 4). The large variety of material with different compositions and grain-sizes also means different deformational responses to the stress as they are carried into the Earth on the subducting plate, and by extension, the different slip behavior (Barnes et al., 2020). Computer numerical modeling has also previously shown that fault surfaces with variable materials might favor transient slow slips over large, sudden ruptures (Saffer et al., 2015), compatible with the observations made from the borehole data.
References
Barnes, P. M., Pecher, I. A., LeVay, L. J., Bourlange, S. M., Brunet, M. M. Y., Cardona, S., … & Wu, H. Y. (2019). Expedition 372A summary. Texas A&M Univ. https://doi.org/10.14379/iodp.proc.372A.101.2019
Saffer, D. M., Wallace, L. M., Barnes, P. M., Pecher, I. A., Petronotis, K. E., LeVay, L. J., … & Wu, H. Y. (2019). Expedition 372B/375 summary. Proceedings of the International Ocean Discovery Program, 372, 1-35. https://doi.org/10.14379/iodp.proc.372B375.101.2019
Harbitz, C. B., Løvholt, F., & Bungum, H. (2014). Submarine landslide tsunamis: how extreme and how likely?. Natural Hazards, 72, 1341-1374.
Mountjoy, J.J., Pecher, I., Henrys, S., Crutchley, G., Barnes, P.M., and PlazaFaverola, A. (2014b). Shallow methane hydrate system controls ongoing,downslope sediment transport in a low-velocity active submarine landslide complex, Hikurangi Margin, New Zealand. Geochemistry, Geophysics, Geosystems, 15(11):4137–4156.https://doi.org/10.1002/2014GC005379
Barker, D.H.N., Henrys, S., Caratori Tontini, F., Barnes, P. M., Bassett, D., Todd, E., and Wallace, L. (2018). Geophysical constraints on the relationship between seamount subduction, slow slip and tremor at the north Hikurangi subduction zone, New Zealand. Geophysical Research Letters, 45(23):12804–12813. https://doi.org/10.1029/2018GL080259
Barnes, P. M., Wallace, L. M., Saffer, D. M., Bell, R. E., Underwood, M. B., Fagereng, A., … & IODP Expedition 372 Scientists (2020). Slow slip source characterized by lithological and geometric heterogeneity. Science Advances, 6(13), eaay3314.
Saffer, D. M., & Wallace, L. M. (2015). The frictional, hydrologic, metamorphic and thermal habitat of shallow slow earthquakes. Nature Geoscience, 8(8), 594-600.
Figure 4. Core and borehole data from site U1520, showing variable lithology of the material being transported into the plate boundary fault zone (Barnes et al., 2020). On the right panels, numbered 1–8, are images of the cores that were drilled during IODP Expeditions 372/375.
