Karen Bemis

Assistant Research Professor

Department of Marine and Coastal Sciences

Office: Rm 204A, Marine Sciences Building

Research Interests

My research interests focus on the application of mathematical analysis, fluid mechanics and computer visualization to problems in physical volcanology, hydrothermal processes and subduction processes.

Seafloor Hydrothermal Systems: My current research on hydrothermal systems focuses on quantifying heat flux and connecting seafloor discharge to crustal processes. Observational data from multi-beam sonar, thermistors, flowmeters, and cameras underlie efforts to quantify discharge rates, model interactions with the ocean, and discover temporal patterns.

 COVIS: The Cabled Observatory Vent Imaging Sonar has been developed by a team of acousticians, physical oceanographers, and engineers to image the 3-D structure of seafloor hydrothermal plumes and map the spatial distribution of diffuse discharge in the surrounding sites. This work was inspired and initiated by Peter Rona.  Our team has collected acoustic data at several hydrothermal sites on the Juan de Fuca Ridge, including ASHES vent field on Axial Volcano, Main Endeavour Field on the Endeavour Segment, and Monolith Vent on the Cleft Segment.  Scientific visualization techniques, such as feature extraction and skeletonization, are combined with acoustic methods, such as Doppler phase analysis, to estimate plume centerlines and properties (such as local maximum and vertical velocity) tied to that centerline; these properties can be compared to qualitative, analytical and numerical models of hydrothermal plumes.

Diffuse flow interactions with ocean currents: A current project uses thermistor data to explore the scales of temporal variation related to the interaction of diffuse discharge and ocean currents. Techniques such as cross-correlation and numerical modeling are used to extract information on flow rates and vent spacing.

Morphology and growth of Scoria Cones: My current research in physical volcanology focuses on the processes that control the map or planform shapes of scoria cones.

Cone Model: Current work focuses on the development of a 3-D numerical model of scoria cone growth. The model treats an eruption as a series of phases (to mimic Strombolian bubble bursts) which consist of a ballistic stage delivering scoria to the deposit, a grain flow stage that adjusts the deposit to maintain realistic slopes, and a lava flow stage to account for the impact of effusive processes.  The basic model is complete but continued efforts is updating the effects of drag force, wind and sloping topography and improving the grain flow module.

Cone Morphology in Volcanic Fields: Cone morphology data from various volcanic fields has been assessed for its implications for differential growth processes. My database of morphologic parameters (height, base diameter, crater diameter, crater depth, etc.) for scoria cones (and other volcanoes) for Guatemala has been updated to include assessments of planform shape. In past projects, 3-D visualization helped constrain the morphologic space occupied by different types of volcanoes, including stratovolcanoes, shield volcanoes, cinder cones, maars and domes; in a three dimensional space, using size, flat-toppedness and slope as axes, the morphologic space of each type overlaps only slightly with the other types.

Scientific and Information Visualization: My research has involved collaboration in a wide variety of projects using visualization and computer graphics to illustrate and understand data from numerical modeling of ocean eddies, job posting databases, visualization literacy, and subduction zone earthquake distributions.

Alpha shape analysis: 3-D visualization of the region occupied by earthquake hypocenters is used to the constrain shape of subducting slabs. The brittle region defined by the region of deep earthquakes can be visualized as a 3-D solid and potentially quantified using Delauny triangularization.

Links to Research Project Pages