Susan Schwartz - US grants

The Cayo Santiago rhesus monkey colony was established in 1939 by transporting 400 adult animals from India to Puerto Rico. This colony has existed since that time with no significant manipulation and careful documentation of the matriline inheritance since 1959. In 1984, intravenous glucose tolerance tests (IV-GTT) were carried out on animals derived from two of the six troops that exist on Cayo Santiago. The results of this study suggest that about 20% of the adult population exhibited carbohydrate intolerance, overt diabetes and/or hyperinsulinemia. The objective of this project is to further characterize the carbohydrate impairment found in the initial IV-GTT by: (1) carrying out the frequently sampled intravenous glucose tolerance test (FS-GTT) in the 45 animals of Groups M and J that showed an abnormal IV-GTT in 1984; (2) to establish the degree of obesity in animals showing impaired carbohydrate intolerance; and (3) to document the presence of an amyloid glycoprotein and/or islet cell antibodies in a selected group of animals. These studies will establish whether the rhesus monkey from Cayo Santiago is a primate model for spontaneous adult onset diabetes and prediabetes.

It is well established that nutritional status plays an important role in the onset of puberty. It has been proposed that changes in the metabolic state of the maturing animal may directly influence neuroendocrine factors associated with the timing of puberty. We propose that diet, in particular, a high fat diet, through metabolic and endocrine changes may directly influence sexual maturation and the timing of first ovulation, independent of changes in overall growth. We will examine the effect of different diets (high fat-high protein, high fat-low protein, high carbohydrate-high protein and standard high protein chow) on growth and sexual maturation and the timing of first ovulation using the prepubertal rhesus female, housed outdoors, as a model. Starting at 12 mo of age, we will examine the effects of diet on: (a) somatic growth, reflected in body weight, crown-rump lengths, percent body fat and adipose cellularity; (b) growth related endocrine factors including growth hormone (GH), somadomedin-C (SM-C), prolactin, glucose, and insulin; (c) food intake and energy expenditure, reflected in basal metabolic rate, and (d) possible seasonal patterns in growth, feeding and energy expenditure. The effect of these regulatory changes in relation to sexual maturation will be examined by monitoring maturational increases in gonadal steroids and gonadotropin secretion. Developmental and diet-induced changes in gonadal status in relation to changes in the metabolic and reproductive state (insulin, GH, SM-C, LH) will be examined by measuring ovarian steroid concentrations and the major pathways for estradiol metabolism. Finally, we will examine more closely effects of diet on metabolic factors (insulin, free fatty acids, glucagon, large neutral amino acids) by measuring concentrations before and after administration of a glucose load (iv glucose tolerance test). This project will provide new information on the effects of diet and metabolism on sexual maturation and the timing of first ovulation.

This research is to investigate the factors that control the localization of moment release at subduction zones. By comparing the positions of maximum moment release between subduction zones with different characteristics and correlating them with a variety of subduction zone parameters, information on the physical processes that influence the localization of moment release will be revealed. Determination of whether earthquakes of very different magnitudes rupture the same regions on the plate interface is important in understanding the role that fault strength plays in the localization of moment release. Since great earthquakes account for the majority of moment release at subduction zones, their influence on seismic behavior is essential to understanding the localization of moment release. This research is a component of the National Earthquake Hazard Reduction Program.

9413787 Schwartz This award provides partial funding for the acquisition of portable geophysical field stations to be used in research and teaching projects in tectonics, Earth structure, and earthquake studies. The equipment of the stations will consist of portable broad band digital seismometers and their data acquisition systems, and receivers to be used in connection with the satellite-based Global Positioning System. The geophysical field stations will be stored and maintained by the Institute of Tectonics at the University of California at Santa Cruz. The University of California at Santa Cruz is committed to providing the remaining funds necessary for the acquisition of these field stations. ***

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9418213 Schwartz This award provides one-half the funding required for the acquisition of equipment to upgrade the computing capabilities in the Institute of Tectonics at the University of California-Santa Cruz. The institution is committed to providing the remaining funds needed to acquire the equipment. The equipment upgrade will be used primarily by the earthquake seismology research group of the Institute of Tectonics, currently consisting of three professors, three research scientists, five postdoctoral fellows, and nine graduate students. The research program in seismology at UC-Santa Cruz encompasses both studies in Earth structure and studies of earthquakes and other sources of seismic waves such as underground nuclear explosions. The research of the group includes processing of very large data sets and executing computer codes with large memory requirements. ***

Funds are being provided for a three year, multi-institutional, two-transect, geodetic and seismic experiment across the Middle America Trench and Costa Rica, immediately above the seismogenic interface between subducting Cocos and overriding Caribbean plates. The PIs will operate GPS, leveling, and digitally recording seismometers on land and deploy ocean bottom seismometers (OBSs) offshore. The goal is to map the three-dimensional distribution and nature of the seismogenic zone, the locked or the partly locked plate interface that generates large earthquakes, for comparison to processes that control the distribution of seismicity and plate coupling. The imaging of the seismogenic zone will be enhanced in the Nicoya and Osa peninsular region because of the close approach of local coastline to the trench axis where the large earthquakes are generated.

EAR-0229876
Susan Y. Schwartz

A first-order characterization of the seismogenic zone, including its geometry
and up and down-dip limits is nearly established in northern and central Costa
Rica. This was accomplished through the deployment of two onshore/offshore
seismic networks directly above the seismogenic zone that were part of a
MARGIN's funded multidisciplinary seismogenic zone experiment (CRSEIZE). This
proposal seeks to: 1) use data collected during this experiment in conjunction
with local network data to establish a similar first-order characterization of
the seismogenic zone in Nicaragua; 2) perform a detailed investigation of the
variations in the transition from inter to intra plate seismicity in northern
Costa Rica and Nicaragua; and 3) evaluate thermal and mechanical models that
have been proposed to control this transition. These golas will be accomplished
by simultaneously inverting local travel time data in northern Costa Rica and
Nicaragua to obtain an high resolution, three-dimensional, P and S wave velocity
structure and accurate hypocentral locations. Earthquake locations coupled with
focal mechanism determinations will allow the active seimogenic zone to be
identified in southern Nicaragua, where the addition of stations from the
northern Costa Rica (Nicoya) network greatly improves station coverage and
hypocentral accuracy.

A network of continuous GPS and six seismometers is being developed to monitor transient strain and seismic events above the subducting slab on the Nicoya Peninsula, northern Costa Rica. This will allow investigation of a number of seismogenic zone processes. One of the most exciting recent discoveries in the solid earth sciences is the occurrence of silent slip or aseismic creep events at subduction zones. The physical processes responsible for these events are not well understood; detection and study of their behavior at several locations is important. Aseismic creep episodes have been observed prior to the occurrence of large earthquakes and therefore may have important implications for earthquake hazard. Creep episodes perturb the surrounding stress field and their occurrence at the down dip edge of the seismogenic zone could bring the megathrust closer to failure. These stress increases are small, however if the fault is close to failure aseismic creep could trigger a large earthquake.

Relative to other subduction zones, Nicoya has a big advantage for this type of project: the peninsula is quite close to the trench. Instruments deployed here are essentially perched directly over the locked part of the plate boundary, enabling high-resolution study of plate boundary strain and seismic processes. The correlation between deep episodic creep and low frequency tremor, recently uncovered at the Cascadia subduction zone, could be significant in deciphering the key physical processes. The project is an international collaboration with scientists from Costa Rica. Germany, Japan and the United States.

0502488
Schwartz

This grant will support acquisition and installation of a 9 station network of continuously operating GPS stations (CGPS) and 3 boreholes broadband seismometers and tiltmeters on the Nicoya Peninsula to investigate slow slip events and episodic seismic tremor at the Costa Rican subduction zone. The new instrumentation will augment 3 existing CGPS stations deployed by Japanese and Costa Rican colleagues, and 6 borehole seismic observatories, being installed by German colleagues. These international collaborations will greatly enhance the ability of the network to address fundamental questions about earthquake processes in this hazardous region. Slow slip events or "silent earthquakes" are a recently observed mode of strain release where slip occurs over an intermediate time scale, usually days to months. This type of motion has been detected at a few subduction zone faults where continuous GPS or borehole tiltmeter networks exist. The processes responsible are poorly understood but slow slip events have been associated with low frequency seismic tremor, possibly caused by the migration of fluids through the shallow subduction system. Increased fluid pressure on the interplate fault could act to weaken it bringing it closer to failure. As a result, slow slip events may indicate pre-rupture fault breakdown prior to the occurrence of a large earthquake. The Nicoya Peninsula borehole seismic and CGPS networks will have sufficient density and sensitivity to detect and study slow slip events and seismic tremor and investigate the processes responsible for their generation.
***

This award supports investigation of the hydration state of subducted lithosphere at the Costa Rica convergent margin. Previous studies have suggested above average slab hydration in this region, which implies anomalous dehydration at depth. This is important because slab dehydration plays a critical role in producing arc lavas and in generating intermediate depth earthquakes within the downgoing slab. Slab dehydration at shallower depth may also be important in influencing seismogenic behavior along the plate interface. Metamorphic dehydration reactions in oceanic crust have been implicated in the serpentinization of the forearc mantle wedge and the termination of interplate earthquakes in some subduction zones. The Costa Rica Seismogenic Zone Experiment imaged a distinct pattern of geodetic locking and microseismicity along the plate boundary in northern Costa Rica. The onset of interplate microseismicity occurs down-dip of the region of geodetic locking, coincident with thermal models of the 200-250 degrees Centigrade isotherms. This has been interpreted as a down-dip weakening of the plate interface due to fluid production from low-grade metamorphic reactions in basaltic crust coupled with a decrease in permeability around 250 degrees Centigrade producing elevated pore pressure and sufficient weakening of the thrust interface to permit earthquake failure. The implication of slab dehydration in the initiation of interplate earthquakes has thus increased the importance of determining the state of hydration of subducting lithosphere. P-to-S converted seismic phases, generated at the crust-mantle (Moho) interface of the subducting Cocos slab, recorded by the Costa Rica Seismogenic Zone Experiment broadband seismometers positioned directly above the slab are being analyzed. Teleseismic converted phases provide a direct method to image the structure of the subducted slab, and are being used to determine velocity structure across the oceanic Moho and relating it to the extent of oceanic crustal hydration. In addition, the velocity structure in the vicinity of the plate boundary is being investigated and related to the onset of seismicity and the inferred weakening of the plate interface. The possible role of a large normal fault outer rise earthquake in hydrating the oceanic crust near the Nicoya Peninsula is being assessed. This work is enhancing the understanding of the velocity structure of the subducting lithosphere and plate interface and its material properties.

Intellectual Merit
The work proposed is to augment, upgrade and extend the monitoring period of an existing network of GPS and seismic instrumentation on the Nicoya Peninsula, Costa Rica. The questions to be addressed by the data collected include: 1) What is the relationship between slow slip, tremor, strain accumulation and interplate earthquakes. 2) What is the role of temperature and fluids in tremor and slip generation? 3) Is the occurrence of fast and slow slip tremor spatially and/or temporally separated? The answers to these questions have important implications for understanding seismic processes at subduction zones.

Broader Impacts
This project includes the training of several Ph.D. students. It also includes technology and science transfer to Costa Rica to improve their monitoring of earthquakes. The PIs propose to travel to 2 minority institutions to recruit students.

The Research Experience in Solid Earth Science for Students (RESESS) program has established itself as a successful program for multi-year summer research internships for Earth science undergraduates from populations underrepresented in science. Students are recruited in their sophomore or junior year and complete 10-week internships that include research, leadership training, an eight-week communication workshop, multi-faceted mentoring, and a final colloquium. Additional funding through this award is being used to take RESESS to the next level of success by expanding the number of interns, extending the scientific content and geographic reach of the program, and building a model for sustainability based on a program infrastructure with disseminated mentoring. The expanded program will support a minimum of 12 interns per year, with students spending their first two years in Boulder and then transitioning to work with research mentors throughout the United States during their 10-week summer experience. RESESS will continue a successful collaboration with the award-winning Significant Opportunities in Atmospheric Research and Science (SOARS) program. Expansion into a more distributed model of mentoring - necessary because there is no central research facility analogous to the National Center for Atmospheric Research (NCAR) for the geology and geophysics community - is being achieved through expanded partnerships. These partners include scientists in the United States Geological Survey (USGS) in Golden, Colorado, at the University of Colorado, Boulder, staff at UNAVCO, and scientists of the UNAVCO and Incorporated Research Institutions for Seismology (IRIS) research consortia, along with new partners in the Colorado Diversity Initiative and the University of California at Santa Cruz. Intern research projects are expected to include topics such as the technical aspects of GPS, analyzing the seismicity of Asian earthquakes, modeling volcanic magma movement, installing GPS networks to monitor regional tectonics, paleoclimate analyses of insect damage to fossil leaves, lineaments in Antarctica, and others. To sustain the program beyond NSF funding, RESESS is exploring the utility of the Business Performance Excellence model, while engaging the community for increased scientific and financial resources and exploring diversified funding sources.

This grant supports a collaborative effort between the University of Miami ? RSMAS (PI: Tim Dixon), the University of California Santa Cruz (PI: Susan Schwartz), UNAVCO and Costa Rican colleague Dr. Marino Protti at OVSICORI to acquire and deploy GPS and seismic equipment on the Nicoya Peninsula, Costa Rica. Observation from this network will directly feed into research efforts supported by the Margins Program (OCE-0841091/Miami-RSMAS/Dixon and OCE-0841091/UCSC/Schwartz). This grant will facilitate an augmentation and upgrade to a current but smaller network of GPS and seismic instrumentation on the Nicoya Peninsula, Costa Rica (funded through EAR- 0502221). The end result will be extended and better constrained geophysical observations in time and space beyond that now being acquired.

This support will add an additional seven GPS sites and upgrade five of the older existing thirteen GPS sites to PBO standards as well as allow for the purchase and installation of four Guralp CMG3 broadband seismic sensors and associated data loggers to replace equipment in the current Nicoya seismic network that are currently on loan. Data from the network will continue to flow to the UNAVCO and IRIS publicly accessible data archives.

The existing Nicoya seismogeodetic network has recorded initial evidence of aseismic slip of the downgoing slab and associated nonvolcanic tremor in May 2007. This expansion of the Nicoya GPS and seismic network will better constrain the time varying strain field and seismic activity. Similar albeit higher resolution space-time observations of subduction zone dynamics within the Cascadia and SW Japan subduction zones have radically changed and challenged our understanding of plate tectonic processes at subduction zones with implications for better understanding seismic hazards. This expansion of the Nicoya Plate Boundary Observatory (PBO) will allow for study of a class of subduction zone with different properties from those of the Cascadia and Japan trenches, perhaps most importantly, temperature/age of the downgoing slab. The Nicoya Peninsula is unique in that it is perched almost directly over the locked part of the plate boundary. As a result, the proposed geophysical observatory will enable high signal/noise (S/N) ratio observations of plate boundary processes. Questions to be addressed by the data collected by these instruments include: 1) What is the relationship between slow slip, nonvolcanic tremor, strain accumulation and interplate earthquakes. 2) What is the role of temperature and fluids in tremor and slip generation? 3) Is the occurrence of fast and slow slip tremor spatially and/or temporally separated? The answers to these questions have important implications for understanding the seismic process at subduction zones.

Broader impacts will include international cooperation and technology transfer, graduate student training with state-of-the-art seismic and geodetic instrumentation and techniques, and improved understanding of earthquake hazards in the region.

This award provides support for "Investigating (Un)Stable Sliding of Whillans Ice Stream and Subglacial Water Dynamics Using Borehole Seismology: A proposed Component of the Whillans Ice Stream Subglacial Access and Research Drilling" from the Antarctic Integrated Systems Science (AISS) program in the Office of Polar Programs at NSF. The project will use the sounds naturally produced by the ice and subglacial water to understand the glacial dynamics of the Whillans Ice Stream located adjacent to the Ross Ice Shelf in Antarctica.

Intellectual Merit: The transformative component of the project is that in addition to passive surface seismometers, the team will deploy a series of borehole seismometers. Englacial placement of the seismometers has not been done before, but is predicted to provide much better resolution (detection of smaller scale events as well as detection of a much wider range of frequencies) of the subglacial dynamics. In conjunction with the concurrent WISSARD (Whillans Ice Stream Subglacial Access and Research Drilling) project the team will be able to tie subglacial processes to temporal variations in ice stream dynamics and mass balance of the ice stream. The Whillans Ice Stream experiences large changes in ice velocity in response to tidally triggered stick-slip cycles as well as periodic filling and draining of subglacial Lake Whillans. The overall science goals include: improved understanding of basal sliding processes and role of sticky spots, subglacial lake hydrology, and dynamics of small earthquakes and seismic properties of ice and firn.

Broader Impact: Taken together, the research proposed here will provide information on basal controls of fast ice motion which has been recognized by the IPCC as necessary to make reliable predictions of future global sea-level rise. The information collected will therefore have broader implications for global society. The collected information will also be relevant to a better understanding of earthquakes. For outreach the project will work with the overall WISSARD outreach coordinator to deliver information to three audiences: the general public, middle school teachers, and middle school students. The project also provides funding for training of graduate students, and includes a female principal investigator.

Deployment of a network of pressure gauges and seismometers on the Hikurangi portion of the subduction zone off North Island New Zealand is designed to record a slow-slip event (SSE) expected to occur on the plate boundary fault in the 2014-2015 timeframe. SSE occur every ~18 months in this region, so documenting the deformation associated with this type of event and comparing that couple-week activity with ongoing microseismicity should illustrate the evolution of forces and associated hazards in this region. Twenty US seafloor instruments, including 10 from OBSIP, will be combined with a similar number of Japanese instruments for ~12 months. These data will be evaluated together with data from onshore geodetic and seismic stations in this international collaboration. Results will inform planning for possible future seafloor drilling by IODP and subsequent in-situ measurements.

Due to the shallow dip of the subducting plate, the Hikurangi site offers a unique opportunity to document the small signals associated with SSE, for which motion is too minor for human perception. Insights into this newly-recognized mode of plate interaction, are expected to be applicable to other convergent margins. How far 'up-dip' the slip extends, whether all the way to the seafloor near the subduction trench or not, is a key unknown in current estimates of earthquake shaking and tsunami hazard. The extent of slow slip can indicate how much stress on the plate boundary fault is relieved versus building up toward an eventual megathrust earthquake.

The plate boundary at convergent margins produces most of the world?s largest earthquakes, threatening local inhabitants and global populations through destructive shaking and tsunami generation. An Mw 7.6 earthquake occurred on 5 September 2012 in Nicoya Peninsula, northern Costa Rica directly beneath a network of seismic and continuous GPS stations. It provides a unique opportunity to study the cycle of a megathrust earthquake in unprecedented detail. This project seeks to better understand the preparation process of megathrust earthquakes by identifying slow preslip and/or patterns in foreshock activity, and evolutions of aftershocks and afterslip induced by the mainshock. Our project has important implications for predictability of large earthquakes, the potential size of the megathrust earthquake, the strong ground motions and associated damage, and tectonic strain accumulation and release during an earthquake cycle.

Major research questions to be addressed include whether there is discernible preparation activity before the mainshock, if distinct regions of the plate boundary host coseismic versus slow and after slip, if slip in the mainshock occurs in regions accumulating strain during the interseismic period, whether aftershocks are driven by afterslip or other processes, and what effect mainshock rupture has on seismic velocities and properties of the plate interface. Because we have been measuring surface deformation and seismicity directly above the megathrust for over a decade preceding the 2012 Nicoya earthquake, we can compare the distribution of coseismic slip with the interseismic strain accumulation pattern, slow slip behavior, and precursory seismicity and address all of these questions in a single location. To ascertain whether any accelerating foreshock activity and aftershock expansion/migration occurs, a complete catalog of seismic activity before and after the mainshock is required. We will use all earthquakes in our existing catalog as templates and scan through continuous records to identify additional events easily missed by automated detection algorithms and visual inspection. Event pairs with the highest correlation coefficients will be grouped into repeating earthquake clusters and used to infer slow-slip and afterslip, and track temporal changes of subduction zone interface properties. We will also detect tectonic tremor long before and after the mainshock and use it as a proxy for slow slip and investigate whether tremor/slow slip events occur before major earthquakes. Finally, we will compare high-resolution co-seismic slip with aseismic slip during postseismic and interseismic period as well as microseismicity to understand different frictional properties of the plate interface. Because of the high-quality data collected over the past decade, and the close proximity to the megathrust, our project could lead to significant advances on how subduction zone properties evolve immediate before and after a major megathrust event.

Collaborative Research: Developing New Science and Technology for Subglacial Studies of the Whillans Ice Plain and West Antarctic Ice Sheet is supported by the Antarctic Integrated System Science (AISS) program in the Antarctic Sciences Section of the Division of Polar Programs within the Geosciences Directorate of the National Sciences Foundation (NSF). The funds will support the design, construction, and deployment of a roving hot water drill and basal ice coring equipment to be deployed in conjunction with the WISSARD (Whillans Ice Stream Subglacial Access and Research Drilling) project during the 2013/2014 field season. The roving hot water drill will be deployed at up to two locations in each of two sites: in the vicinity of Subglacial Lake Whillans, and at the grounding line where the drainage from Subglacial Lake Whillans empties into the sub-ice shelf cavity. The ice coring equipment will only be used at the grounding line location. All locations are at the edge of the Ross Ice Shelf, connected to the West Antarctic Ice Sheet (WAIS).

Intellectual Merit: The new equipment will be used to augment two on-going projects occurring in the Whillans Ice Stream area, WISSARD, that focuses on understanding the biology, geochemistry, paleogeology, and hydrological/glaciological interactions of the Whillans Subglacial system, and a second project focused on the micro-earthquakes associated with the sticky spots found in the Whillans area. The basal ice corer will add significant data to the WISSARD project, and the roving drill will provide access holes to insert within glacial seismometers that will allow a much better understanding of the micro-earthquakes. The within glacial seismometers will build on the collection of surface seismic data from 2012-13 that are characterized by repeated high frequency events interpreted as basal earthquakes. These earthquake events were not detectable at stations only 20 km away, so obtaining a better understanding of these physical mechanisms will be very useful for understanding basal ice motion and friction.

Broader Impacts: In addition to the contributions to the understanding of ice dynamics mentioned above, future availability of a roving hot water drill system and related coring capabilities will result in increased research opportunities for researchers from a range of disciplines interested in the interface between the base of the ice sheets and the underlying substrate. The project will also support the development of the US's technical expertise in hot water drilling. Finally, the project will provide further funding of the public outreach and education started by the WISSARD project. The WISSARD outreach and education activities have been exceptional to date, and it is expected that additional activities enabled by this new award will be exceptional as well.

In order to remain vital, the American economy must compete globally, attract investment, and create jobs. This project will address the shortage of qualified STEM technicians and professionals in the nation's workforce by increasing the number of well prepared graduates with an Associate of Science degree with a focus on biology, chemistry, or mathematics or an Associate of Applied Science in engineering from Asheville-Buncombe Technical Community College (A-B Tech). The project will amass multiple stakeholders including faculty members and collaborators from public schools, 4-year institutions, and industry to serve a minimum of 134 academically talented and financially needy students.

The primary goal of the project is to bolster student persistence and achievement through support services (co-advising, case management, tutoring, mentoring, and internships) and academic enrichment activities (seminars, service learning, college tours, and industry visits). A secondary goal is to develop a viable and reproducible model for joint high school, community college, and university pathway efforts to address an increasing labor shortage of well prepared STEM technicians and professionals. Formative evaluation will focus on student participation in student support services and engagement in enrichment activities (surveys and focus groups). Summative data collection will focus on student persistence and completion information (mid-term and final grades, re-enrollment, and goal completion). Dissemination of results will be achieved through presentations at the NC Community College Student Development Personnel Association and NC Community College System Office State-wide conferences and through the institution's AB-Tech Education Journal.

This project evaluates the role that water and rock/ice properties at the base of a fast moving glacier, or ice stream, play in controlling its motion. In Antarctica, where surface melting is limited, the speed of ice flow through the grounding zone (where ice on land detaches, and begins to float on ocean water) controls the rate at which glaciers contribute to sea level rise. The velocity of the ice stream is strongly dependent on resistance from the bed, so understanding the processes that control resistance to flow is critical in predicting ice sheet mass balance. In fact, the Intergovernmental Panel on Climate Change (IPCC) recognized this and stated in their 4th assessment report that reliable predictions of future global sea-level rise require improved understanding of ice sheet dynamics, which include basal controls on fast ice motion. Drilling to obtain direct observations of basal properties over substantial regions is prohibitively expensive. This project uses passive source seismology to "listen to" and analyze sounds generated by water flow and/or sticky spots at the ice/bed interface to evaluate the role that basal shear stress plays in ice flow dynamics. Because polar science is captivating to both scientists and the general public, it serves as an excellent topic to engage students at all levels with important scientific concepts and processes. In conjunction with this research, polar science educational materials will be developed to be used by students spanning middle school through the University level. Starting in summer 2015, a new polar science class for high school students in the California State Summer School for Mathematics and Science (COSMOS) will be offered at the University of California-Santa Cruz. This curriculum will be shared with the MESA Schools Program, a Santa Cruz and Monterey County organization that runs after-school science clubs led by teachers at several local middle and high schools with largely minority and underprivileged populations.

This proposal extends the period of borehole and surface geophysical monitoring of the Whillians Ice Stream (WIS) established under a previous award for an additional 2 years. Data from the WIS network demonstrated that basal heterogeneity, revealed by microseismicity, shows variation over scales of 100's of meters. An extended observation period will allow detailed seismic characterization of ice sheet bed properties over a crucial length scale comparable to the local ice thickness. Due to the fast ice velocity (>300 m/year), a single instrumented location will move approximately 1 km during the extended 3 year operational period, allowing continuous monitoring of seismic emissions as the ice travels over sticky spots and other features in the bed (e.g., patches of till or subglacial water bodies). Observations over ~1km length scales will help to bridge a crucial gap in current observations of basal conditions between extremely local observations made in boreholes and remote observations of basal shear stress inferred from inversions of ice surface velocity data.

This project investigates a rapidly moving section of the West Antarctic Ice Sheet known as the Whillans Ice Stream. Ice streams and outlet glaciers are the major pathways for ice discharge from ice sheets into the ocean. Consequently, understanding ice stream dynamics, specifically the processes controlling the frictional resistance of ice sliding on sediments at its base, is essential for predictive modeling of how Earth's ice sheets will respond to a changing climate. Rather than flowing smoothly, Whillans Ice Stream advances in stick-slip cycles: brief periods of rapid sliding, equivalent to magnitude 7 earthquakes, alternating with much longer periods of repose. The PIs will perform simulations of these stick-slip cycles using computer codes originally developed for modeling tectonic earthquakes. By matching observed ice motions, the PIs will constrain the range of frictional processes acting at the base of the ice stream. An additional focus of the project is on brittle fracture processes in ice, expressed through seismic waves radiated by faulting and/or crevassing episodes that accompany the large-scale sliding events. An understanding of ice fracture provides a basis for assessing the susceptibility of ice shelves to rifting and catastrophic disintegration. Project results will be incorporated into outreach activities (from elementary school to community college events) as well as a polar science class for the California State Summer School for Mathematics and Science (COSMOS) program for high school students.

Simulations of the stick-slip cycle will employ 3D dynamic rupture models that simultaneously solve for the seismic wavefield and rupture process, consistent with elastodynamic material response and friction laws on the ice stream bed. Stresses and frictional properties will be varied to achieve consistency with surface GPS and broadband seismic data as well as borehole seismograms from the WISSARD project. The results will be interpreted using laboratory till friction experiments, which link velocity-weakening/strengthening behavior to temperature and water content, and to related experiments quantifying basal drag from ice flow over rough beds. The source mechanism of seismicity accompanying the slip events (shear faulting versus crevassing) will be determined using 3D waveform modeling in conjunction with mechanical models of the seismic source processes. This proposal does not require fieldwork in the Antarctic.

Subduction zones, where one tectonic plate bends down beneath another tectonic plate, are important in the evolution of Earth's surface as well as being a major earthquake and tsunami hazard for society. In the last 15 years, dense Global Positioning System (GPS) and earthquake observations made at subduction zones have revealed a new style of fault slip. In addition to continuous slip and sudden earthquake motion, many faults experience slow slip. In some instances, a relationship between slow slip and damaging large earthquakes has been observed. Most observations of slow slip occur at 20-40 km depth below the seafloor. At the Hikurangi margin offshore of New Zealand, slow slip also occurs at shallow depths, but detailed investigation of shallow slow slip has been hampered by the lack of suitable seafloor observations. Understanding the extent, distribution, and range of physical conditions for shallow slow slip events is important, especially since the shallow fault interface is where tsunamis are generated by earthquakes. This project uses recently collected ocean bottom seismic and absolute pressure gauge data from the Hikurangi margin to investigate the relationship between earthquake and slow slip and the physical conditions that favor them. Results of this research will be incorporated into an earthquake science course for the California State Summer School for Mathematics and Science program for high school students at the University of California-Santa Cruz. This project involves the mentoring and training of three graduate students and two to four undergraduate interns, including at least one from an underrepresented group in the Earth Sciences. All students will benefit by receiving training from researchers at different institutions.

A large shallow slow slip event occurred in October 2014, directly beneath the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip instrument array, a major U.S. led international experiment with Japanese and New Zealand researchers. The experiment was designed to investigate the physical environment that hosts shallow slow slip and its relationship to destructive, seismic slip on the Hikurangi subduction thrust. This project will build on the initial data analysis from this experiment to tackle four main objectives: 1) to improve initial tremor and earthquake detection and location using the PageRank technique and matched filtering cross correlation, 2) to investigate changes in coulomb failure stress imparted on the megathrust from the 2014 slow slip event and compare it to earthquake and tremor locations to test whether static stress changes can explain their location, 3) to determine earthquake source parameters and explore their spatial and temporal relationships with slow slip, geodetic coupling and physical properties of the plate interface and 4) to improve images of seismic velocity and attenuation structure using body wave velocity and attenuation tomography and ambient noise surface wave tomography. This project will complement similar efforts in Cascadia and Japan, allowing comparison of the properties and environment of shallow and deep slow slip and build a detailed picture of the relationship between seismic and aseismic slip and its dependence on the velocity and attenuation structure.

Part 1
GEOsciences Diversity, Excellence, and Support (GEODES) is a program designed to increase retention and success of under-represented students in the Earth and Planetary Science Department at UCSC, an ongoing challenge for the Earth sciences in the USA. The program provides sustained mentoring, networking, reliable and current information about career paths and opportunities, as well as and professional development. This program will improve retention of students entering the major, ensure a positive and productive experience of a more diverse group of students in the EPS department and help students make the transitions from undergraduate to graduate study and beyond. Ultimately, this program will reduce disparities in graduation rate, course success, and overall GPA among Earth and Planetary Science Department under-represented undergraduates and increase the preparation and transfer of our primarily Hispanic under-represented students to graduate school and/or the geoscience workforce.

Part 2
GEODES goals are to reduce disparities in UM outcomes in passing courses, overall GPA, graduate school admission, and to improve job placement for UM and non-UM majors. To accomplish this goal, we will focus on UM academic support and building a sense of belonging within the Earth science community. Specifically, GEODES will focus on three activities: (1) Create a cohort-based support program, targeted to UM students called GEOACE, modeled on UCSC's successful Academic Excellence (ACE) program which has significantly increased UM retention and GPA in introductory STEM courses. Students in GEOACE will receive extra academic support (skills workshops, EPS course-based problem-solving sessions and professional development advising). (2) Offer a paid summer internship to UM students to expose them to geoscience work options and develop skills and connections to help them get jobs or aid in admission to graduate school. (3) Foster a geoscience student community and near-peer support system via a GeoSlugs Lounge Program. Open to all EPS undergraduate students, the Lounge will be a welcoming space to gather, develop friendships and get tutoring and mentoring from graduate students (guided, course-related problem solving as well as general advice and support). GEOACE instructors and Lounge tutor/mentors will receive pedagogy training through ACE.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Some landslides creep steadily for years or decades. In others, the creep appears similar, then abruptly transitions to catastrophic failure. Distinguishing these two scenarios is crucial for landslide hazard mitigation. However, the mechanistic origins of landslide friction remain unclear, which limits our understanding of how, when, and why landslides sometimes accelerate catastrophically, whereas others creep for decades. This project will advance understanding of landslide friction by combining deformation measurements and seismology at two distinct sites that most likely represent the two scenarios above. One is a well-studied slow landslide (Oak Ridge earthflow in California), while the other is a newly identified slow landslide near Columbia Glacier in Alaska. Whereas Oak Ridge earthflow has exhibited slow sliding for nearly a century, the Columbia Instability is in a setting where the investigators expect that glacier debuttressing of the slope will lead to acceleration and possibly catastrophic failure. The project has implications for natural hazard assessment and mitigation. The team will produce a short science documentary, create a public map of Prince William sound, coordinate among state and federal agencies, and train one PhD student.<br/><br/>This project aims to advance understanding of why frictional asperities in landslides sometimes coalesce catastrophically, whereas others remain distinct, permitting creep for decades despite velocity-weakening friction. Currently there is very little monitoring of landslides over the temporal and spatial scales that would be required to more clearly illuminate the mechanics of landslide friction. This project will aim to bridge this gap by combining deformation monitoring and seismology at a well-studied and well-instrumented slow landslide (Oak Ridge earthflow in California) and an incipient bedrock failure near Columbia Glacier in Alaska. Whereas Oak Ridge earthflow has exhibited stable creep for nearly a century, the Columbia glacier site is in a setting where the slope will likely undergo acceleration due to glacial debuttressing, and this acceleration may lead to catastrophic failure. Field deployments will focus on imaging the spatial and temporal evolution of slip and micro-seismicity in two settings in order to 1) test at Oak Ridge between two different models for how frictional creep associated with stick-slip motion is possible in landslides, and 2) understand at Columbia glacier how velocity weakening asperities grow as creep accelerates due to glacial debuttressing - a process that sometimes culminates in catastrophic failure.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.