This week is shortened by the Thanksgiving holiday, and this weekly report is correspondingly shorter as well.
Last Friday’s episode of National Public Radio’s Science Friday focused on geoengineering (https://www.sciencefriday.com/episodes/november-17-2017/), and Peter Kelemen was among the participants. Peter spoke about his work on carbon capture and storage, but he cautioned that any geoengineering effort should not be viewed as a “Get out of jail free” card to avoid cutting back on greenhouse gas emissions and increasing our reliance on renewable energy sources.
The R/V Marcus Langseth this week is more than halfway through the SHIRE (Seismogenesis at Hikurangi Integrated Research Experiment) project to study the structure and mechanics of the convergent plate boundary east of New Zealand’s North Island. Sean Higgins reported on Monday that the ship had collected about 3,000 of the planned 5,300 km of airgun lines, both shooting to ocean-bottom seismometers and conducting multichannel seismic imaging with the Langseth’s 12.5-km-long streamer. Also on Monday, I heard from the cruise’s chief scientist and Lamont alumnus Nathan Bangs, of the University of Texas at Austin. Nathan wrote, “We are doing very well. Every line so far looks like it belongs in a textbook. The Langseth and crew have been great, and I look forward to a few more weeks of exciting data acquisition.”
Julian Spergel kept up the blog from the Rosetta-Ice team now in Antarctica to complete the geophysical survey of the Ross Ice Shelf and the bathymetry of the sea floor that underlies it (http://www.ldeo.columbia.edu/research/blogs/decoding-mysteries-ross-ice-shelf). The theme of yesterday’s posting was not surveying, however, but the extreme weather of the region that has kept the team confined to McMurdo until flying conditions improve.
Lamont’s Annual Report for fiscal year 2017 was posted on our web site this week (https://issuu.com/earthinstitute/docs/ldeo_annual_20report_2017_v16_digit?e=4098028/55352598). Among the highlights of Observatory research over the past year described in the report are the work of Sonya Dyhrman’s group on interactions among microbes at the base of the marine food web and changes to marine life that can be expected in a warming world, the investigations of Joaquim Goes’s group of the invasive species Noctiluca scintillans and its ability to outcompete the native diatoms and other phytoplankton that once anchored the base of the food web in the Arabian Sea, and the work of Kevin Uno and his colleagues on the influence of past climate change in eastern Africa on the evolution of vegetation and the diets of the region’s mammals, including the ancestors of modern humans. There are stories on the finding by Robin Bell, Jonathan Kingslake, and their colleagues that surface meltwater drainage systems on the Antarctic ice sheets and ice shelves are more widespread in the austral summer than previously appreciated, and the demonstration by Joerg Schaefer, Gisela Winckler, and their coauthors, from measurements of cosmogenic nuclides in bedrock recovered from the bottom of a 3-km-long ice core that Greenland must have been essentially ice free for substantial periods during the last Ice Age. Other articles describe efforts by Adam Sobel and others to assess the likelihood and impact of a major tropical cyclone that makes landfall in the vicinity of Mumbai, India, a coastal city of low elevation and dense population; the inference by Anne Bécel and coworkers that a segment of the Alaska subduction zone without a recent large earthquake has strong structural similarities at depth to the site of the great tsunamigenic Tohoku, Japan, earthquake of 2011, suggesting that the tsunami risk in Alaska may have been underappreciated; and Ryan Abernathey’s leadership of the Pangeo project, which aims through new software to give climate scientists access to the rapidly expanding set of climate models of ever improving resolution and increasing size. Stories on Lamont’s education and development programs and on awards and honors to Lamont scientists, along with the Observatory’s annual financial summary and an appreciative call out to Lamont’s generous donors this past year, round out the report.
On Monday, Nature Geoscience published online a paper coauthored by Suzanne Carbotte, James Gibson, and their colleagues on the relation between the state of consolidation of shallow sediments along the Cascadia subduction zone and the slip behavior of the megathrust plate-boundary fault. Offshore of Washington, on the basis of seismic images collected from the R/V Langseth and seafloor drilling data, the team – led by Lamont alumna Shuoshuo Han, now at the University of Texas at Austin – found that sediments near the deformation front and in the outer wedge are strongly consolidated, little sediment appears to be subducted, and the megathrust is thought to be strongly locked. Offshore of central Oregon, in contrast, sediments are substantially less consolidated, and subducted sediments likely host elevated pore pressures that lessen the tendency for locking along the megathrust. A Kevin Krajick press release on the paper’s findings is on our web site (http://www.ldeo.columbia.edu/news-events/ocean-sediments-pacific-coast-may-feed-tsunami-danger), and the story was picked up by Newsweek (http://www.newsweek.com/pacific-northwest-may-be-most-risk-big-one-due-seafloor-sediments-717632) and other media yesterday.
May you take advantage of the Thanksgiving holiday to spend time with family and friends. May you also join me in giving thanks that we at Lamont are able to devote our working hours to improving our understanding of the most fascinating planet known, and to ensuring that our world will continue to be hospitable for the generations that will follow and for all of Earth’s species with which we share our home.
Sean