Thursday, November 29
Scripps Seaside Forum Auditorium
11:30 a.m. Pizza will be served
12:00 p.m. Talks begin
While single-use cups and plates will be available, we are asking everyone to bring their own reuseable items.*
Please join us for the Institutional Seminar Series - lunch sponsored by the Director's Office featuring the following speakers:
How is oceanic seafloor created?
New seafloor is continuously formed at the center of Earth's deep oceans, where the tectonic plates spread apart and cause hot magma to rise to the surface. Where the plates move apart more slowly, as happens over vast areas of the Atlantic, Indian and Arctic oceans, rocks from Earth's mantle are dragged up to the seafloor by slip on long-lived faults called detachments, without the presence of magma. Creation of oceanic seafloor by slip on these recently discovered faults is poorly understood, yet may play a fundamental role in paving a large part of our planet's surface, and explain the presence of mysterious deep-sea vent ecosystems. One of the best ways to understand the behavior of these faults is to study the seismic waves caused by the small earthquakes that are triggered as the faults slip. Here I will talk about earthquake data from a segment of the Mid-Atlantic Ridge near 13°N, where detachment faults are prevalent. The data were recorded by ocean bottom seismographs designed here at Scripps, and placed on the seabed in 2014, as part of an international effort to understand how the oceans are formed. The data show that these faults can generate thousands of tiny earthquakes, and are more complex than previously thought.
Monitoring Earth's ice sheets (and other features) with satellite altimetry
Loss of ice from the ice sheets is accelerating and will soon become the largest contributor to sea-level rise. In Antarctica, ice shelves provide mechanical support to “buttress” the seaward flow of grounded ice, so that ice-shelf thinning and retreat result in enhanced ice discharge to the ocean. Ice shelves are susceptible to changes in forcing from the atmosphere and ocean, which both change on multiple timescales to modify mass gains and losses at the surface and base. The only viable way to monitor the full extent of the ice shelves while capturing the relevant time scales is by satellite. I will show some highlights of analyses of time series of ice-shelf surface elevations derived by my group from satellite radar altimetry from four ESA satellites (ERS-1 & -2, Envisat, CryoSat-2) between 1994 and 2017. These examples demonstrate the capability of long and continuous records from satellite altimeters, allowing us to improve our understanding of what is causing ice-shelf mass changes and stability. As the satellite record lengthens, e.g. with NASA’s ICESat-2 (launched 15 Sept 2018), we expect to reach the point where we can confidently include these processes in models of ice-sheet response to climate changes, which will improve projections of future sea level rise. I will show some early results of ICESat-2 over both Antarctica and Greenland, and also some other results that will be of interest to the Scripps community, in particular mapping of near-shore bathymetry in clear water.
*The University of California system is committed to going zero waste by 2020, and we’re already diverting 69% of our solid waste from landfills system wide. UC San Diego needs everyone to pitch in with waste reductions efforts. Bring your own plate and cup to the Institutional Seminar instead of using single-use items. #MyLastTrash