PhD

2009 (Expected)

Geophysics, California Institute of Technology, Pasadena, CA, U.S.A.

Research Focus: Analytical/Semi-Analytical Modeling, Finite Element modeling, and Inverse Theory

PhD Thesis: Appropriate Models for Interpreting Interseismic Geodetic Data in Subduction Zones

M.S.

2005

Geophysics, California Institute of Technology, Pasadena, CA, U.S.A.

Coursework: Geophysics, Mechanics, Finite Element Modeling. GPA: 4.00

Oral Exam Propositions: 1) A Suction Mechanism for Iron Entrainment into the Lower Mantle,
                                        2) Mechanical Modeling of Interseismic Deformation in Subduction Zones.

M.S.

2003

Geological Sciences, University of Kentucky, Lexington, KY, U.S.A.

Coursework: Geology, Numerical Methods, Finite Difference Modeling. GPA: 4.00

M.S. Thesis: Nonlinear, 2D asperity scale frictional melting model.

M.S.

1997

Engineering, University of Cincinnati, Cincinnati, OH, U.S.A.

Major: Environmental Engineering - Air Pollution Control & Modeling.

Coursework: Dynamical Systems Analysis, Aerosol Transport Theory, Air-Pollution Control. GPA: 3.69

M.S. Thesis: Modeling urban ozone dynamics in the Cincinnati area

B.Tech.

1994

Mechanical Engineering, Indian Institute of Technology (IIT)-Bombay, Mumbai, India.

Major: Thermal and Fluid Sciences & Engineering. GPA: 3.25; Major GPA: 3.49

B.Tech Thesis: Modeling Gas-Liquid Slug Flows in Horizontal Channels

Environmental Engineer 1997-2002

Science Applications International Corporation (SAIC), Air Resources Division, Cincinnati, OH.

Responsibilities: Air-quality modeling; Compliance site-inspections; Modeling multi-pathway pollutant transport and risk assessments in diverse industries; Testing/evaluation of software interface and accuracy of Earthsoft’s GIS based Environmental Quality Database System (EQUIS), in order to check the reliability of this environmental data management/analysis platform for monitoring & remediation projects (http://www.epa.gov/ORD/SITE/reports/540r02503/540r02503.pdf).

Gutenberg Fellowship
Seismological Laboratory, Caltech 2003

Department-wide competitive award given to the best incoming PhD student.

Commonwealth Research Award (CRA)
Univ. of Kentucky: 2002

University-wide competitive award by the Dean of Academic Research, for exceptional research presented at a major national conference.

Pirtle Fellowship
Dept. of Geosciences, Univ. of Kentucky: 2001 & 2002

A department-wide competitive award given to outstanding incoming graduate students as a 2-year annual stipend (on top of RA/TA award).

Graduate Research Assistantship
Dept. of Geoscicences, Univ. of Kentucky: 2001-2003

NSF grant to Prof. Kieran O'Hara, for investigating frictional melting in fault zones.

University Summer Research Fellowship (USRF)
Univ. of Cincinnati: 1996

University of Cincinnati – A university-wide competitive award given to outstanding independent research problems.

99.4^th percentile,
Indian Institute of Technology – Joint Entrance Examination, India: 1990

Ranked in the top 0.6% out of roughly 100,000 pre-screened candidates in the national level aptitude test in Math, Physics, and Chemistry, for admission to the prestigious Indian Institutes of Technology (IIT).

Numerical Methods:

Finite Element & Finite Difference Methods, Inverse Theory (Optimization, Bayesian Methods)

Programming Languages:

Fortran 95/90/77, Python-Numpy-Scipy, Matlab, C, MPI

Software Applications:

Matlab, GMT, SAC, ArcGIS

Operating Systems:

Unix/Linux/OS-X Shell scripting, OS-X & Windows XP administration

Hardware & Networking:

Building and upgrading PCs, Windows NT Peer-to-Peer Network setup and maintenance

Research Interests

I want to model lithospheric deformation at convergent plate margins to infer the rheology of the crust and upper mantle over timescales of thousands to millions of years. My hope is to constrain the rheology of the fault-zone as well as the bulk rheology of the accretionary prism, continental and/or oceanic crust, and upper mantle, consistent with the evolution of surface topography over this wide range of timescales. Towards this end, I want to use geodetic, seismic, and geologic data to constrain rheology in the context of semi-analytical and/or numerical models of mechanical deformation. Other process that can significantly affect crustal strength (and hence, crustal rheology) include fluid and heat transport. I want to model hydrothermal processes within the context of crustal deformation near both convergent and divergent plate margins. I also want to understand the energy efficiency of subduction, and its implications for the rheology of the upper and lower mantle. This is linked to the bigger problem of long-term cooling of the Earth's interior. I am therefore interested in the physical mechanisms that control the structure and composition of the core-mantle boundary (CMB) region, as well as the shape, structure, and rheology of the D'' layer.

Manuscript Reviews

Journal: Earth, Planets, Space

Graduate Teaching Assistant, Seismological Laboratory, Caltech

Summer, 2005 (FY 2004-05)

Field Geophysics (Prof. Rob Clayton): Developed Matlab GUI for a Seismic refraction code.

Summer, 2006 (FY 2005-06)

Field Geophysics (Profs. Rob Clayton, Mark Simons, Joann Stock): GPS, gravity, magnetic, seismic, and resistivity field surveys in Chalfant Valley, eastern California.

Spring, 2007 (FY 2006-07)

Geodynamics (Prof. Mike Gurnis)

Fall, 2007 (FY 2007-08)

Inverse Theory (Prof. Malcolm Sambridge, visiting from ANU)

Graduate Teaching Assistant, Dept. of Civil & Environmental Engg., Univ of Cincinnati

Spring, 1996

Aquatic Chemistry

Fall, 1996

Fluid Mechanics - Hydraulic systems (Prof Shafiq Islam)

Peer Tutor
Univ of Cincinnati, 1994-95

Subjects: Mathematics & Physics (Undergraduate) for Science majors. Coached and mentored undergraduate students as part of a university-wide learning assistance program for 1 yr.

NSS Tutor
IIT-Bombay (India), 1990-92

Subject: Mathematics (Primary/Middle-school). Child literacy program volunteer for the National Social Service (NSS) corps. Mentored young kids from poor neighborhoods for 1 yr.

In Prep

Kanda, R. V. S., E. A. Hetland, and M. Simons (2009), Can Interseismic Geodetic Observations Resolve Persistent Rupture Asperities?

In Press

Kanda, R. V. S., and M. Simons (2009), An Elastic Plate Model for Interseismic Deformation in Subduction Zones, J. Geophys. Res.

Published

Thomas, W. A., R. V. S. Kanda, K. D. O'Hara, D. M. Surles (2008), Thermal Footprint of an Eroded Thrust Sheet in the Southern Appalachian Thrust Belt, Alabama, USA, Geosphere, 4(5), p. 814-818, doi 10.1130/GES00168.1.

Published

Kanda, R. V. S., and D. J. Stevenson (2006), Suction mechanism for iron entrainment into the lower mantle, Geophys. Res. Lett., 33, L02310, doi:10.1029/2005GL025009.

Talk

Poster

Summer, 2006

Neotectonics and Quaternary Geology of the Tien Shan Foreland Basin, Xinjiang, China (2-week Field Trip: Profs. Jean Philippe Avouac, and Rob Clayton):Participants helped conduct a seismic survey at the Anjihai anticline (northern Tien Shan), and visited several areas in the foreland basins north & south of the Tien-Shan.

Summer, 2005

Geophysical Survey of southern Chalfant Valley, Eastern California (1-week Field Class):
Teaching Assistant, Caltech - Ge 111a/b, Field Geophysics (Profs. Rob Clayton, Joann Sotck, Mark Simons)
Supervised and assisted students in carrying out GPS, gravity, & magnetic surveys.

Summer, 2004

Geophysical Survey of Deep-Springs Valley, Eastern California (1-week Field Class):
Caltech - Ge 111a/b, Field Geophysics (Profs. Rob Clayton, Joann Sotck, Mark Simons)
Extensive surveys were performed at 2 different locations of this valley using GPS, seismic, gravity, magnetics, GPR, & resistivity. The data were analyzed to infer a consistent geologic structure beneath the valley floor.

Outdoor skills: Orienteering, backpacking, endurance bicycling (road) and running, swimming, SCUBA diving, sea-kayaking.

Ph.D/M.S. Research
(Caltech)

(Current Research)

Kanda, R. V. S., E. A. Hetland, M. Simons, S. E. Owen, and F. W. Webb (2009), Can Interseismic Geodetic Observations Resolve Persistent Rupture Asperities? A study of the Japan trench off Tohoku. In Prep

Published earthquake source inversions based on seismological data for the Tohoku region of Japan suggest that some large earthquakes (M>7) have repeatedly ruptured the same region of the fault (i.e., asperities), while others have ruptured closely clustered asperities. In contrast, inversions of geodetic data from interseismic periods produce models that are locked over more spatially extensive regions. These broad and smooth regions may be a consequence of lack of model resolution and a resulting need for regularization when using onshore geodetic data. Here, we test the hypothesis that mechanical coupling on inferred asperities alone is sufficient to explain available geodetic observations – i.e., asperities persist across earthquake cycles, and that these data do not require slip along additional regions on the megathrust. To address this question, we use a 3-D mechanical model of stress-dependent interseismic creep along the megathrust, that is consistent with a given frictional rheology and the known spatio-temporal distribution of large earthquakes. These mechanical models also predict a relatively smooth and long wavelength surface velocity field late in the seismic cycle. We are testing if this “physical” smoothing preserves any signature of the original asperities, in contrast to the artificial smoothing produced by model regularization.

(In Press)

Kanda, R. V. S., and M. Simons (2009), A Plate Model for Interseismic Deformation in Subduction Zones, J. Geophys. Res., In Press.

Geodetic observations of interseismic surface deformation near subduction zones are frequently interpreted using simple elastic dislocation models. In this theoretical study, we develop a kinematically more intuitive elastic dislocation model - the elastic subducting plate model (ESPM) - having only two more degrees of freedom than the well established backslip model (BSM): an elastic plate thickness and the fraction of flexural stresses due to bending at the trench that are released continuously. The ESPM (i) predicts no net long-term vertical offset between the subducting and over-riding plates, and (ii) predicts the correct amplitude and direction of motion for the former. We show that the ESPM reduces to the BSM (a) in the limiting case of zero plate thickness, (b) for a plate of finite thickness, if the stresses associated with bending at the trench are released continuously and completely in the shallow parts of the subduction zone, or (c) much deeper (> 100 km). However, if at least part of the bending stresses are released episodically in the shallow parts of the subduction zone (via seismic or aseismic events), then the predicted surface velocities of these two models can differ significantly within a distance of several locking depths from the trench. An important consequence of (a) is that when applying the BSM to a non-planar megathrust, backslip must be assigned onto the actual non-planar interface, instead of to its tangent plane at the bottom of the locked zone.

(Published)

Kanda, R. V. S., and D. J. Stevenson (2006), Suction mechanism for iron entrainment into the lower mantle, Geophys. Res. Lett., 33, L02310, doi:10.1029/2005GL025009.

Perturbations in the Earth's rotation rate at decadal time periods strongly favor the existence of dissipative coupling at the Core–Mantle Boundary (CMB). Here, we explored the plausibility of maintaining a conducting layer on the mantle-side of the CMB, which can couple the outer core and mantle through Lorentz torques. We propose a suction mechanism that maintains a porous medium on the mantle side of the CMB, with the interconnected pore-space partly or entirely filled with liquid iron up to a thickness of ∼1 km. The suction arises from the deviatoric stresses supported by the mantle-solid in regions of mantle downwelling. Infiltration of liquid iron occurs by percolation, but is inhibited by the rate of viscous dilation of the solid mantle. Our model enables core-mantle material exchange, and maintains a thin conducting layer that has seismic detection potential. Our model is only marginally satisfactory in explaining the inferred CMB coupling.

Independent Research
(U. Kentucky)

(Published)

Thomas, W. A., R. V. S. Kanda, K. D. O'Hara, D. M. Surles (2008), Thermal Footprint of an Eroded Thrust Sheet in the Southern Appalachian Thrust Belt, Alabama, USA, Geosphere,, 4(5), p. 814-818, doi 10.1130/GES00168.1.

The Jones Valley thrust fault in the southern Appalachian thrust belt in Alabama is exposed along a northwest-directed, large-scale frontal ramp, with the leading part of the thrust sheet having been eroded. Previously published and newly collected vitrinite reflectance data from Pennsylvanian coal beds document a distinct, northeast-trending, elongate, ovoid-shaped thermal anomaly northwest of the trace of the Jones Valley fault. My contribution to this paper was the 3D analytical model for heat conduction after “instantaneous” emplacement of a rectangular thrust sheet, that was designed to test whether the documented thermal anomaly may reflect a former thrust sheet cover. Owing to the 3D nature of the solution, the geothermal gradient reaches a steady state faster than the 1 D model. The original geotherm is never fully re-established even for long times because of lateral cooling in the hanging wall, resulting in less heating of the footwall. The thickness and extent of the thrust sheet from the thermal model are consistent with both the vitrinite reflectance data as well as the balanced and restored cross sections of the thrust sheet.

MS Thesis
(U. Kentucky)

(In Prep, pending code upgrade)

A 2D Nonlinear Asperity Scale Frictional Melting Model.
Research Advisers: Prof. Kiren O'Hara (Geol), and Prof. Jim McDonough (Mech. Engg.)

M.S. Thesis
(U. Cincinnati)

Urban Ozone Dynamics: An analysis of the Cincinnati Airshed.
Research Advisers: Prof. Pratim Biswas, and Prof. Shafiq Islam (both from Civil & Environ. Engg.)

I applied EPA’s Urban Airshed Model (UAM-IV) – a 3D finite-difference photochemical grid model - in order to identify the controls for urban ozone concentrations in the Cincinnati airshed. The model calculates the concentrations of both inert and chemically reactive pollutants by simulating the physical and chemical processes in the atmosphere affecting pollutants. I tested model sensitivity to pollutant source distributions and meteorological parameters. Principal-component analysis of modeled ozone distributions were used to determined the primary factors influencing ozone concentrations, and suggested potential control measures.

B.Tech Thesis
(IIT-Bombay)

Experimental Observations and Modeling of Gas-Liquid Slug Flow in Horizontal Channels.
Adviser: Prof. Kannan Iyer (Mechanical Engg.)

Modeled gas-liquid slug flow, slug frequency, and gas-entrainment in horizontal circular and coaxial channels. Our goal was to understand the conditions favorable to the slug flow regime, which reduces the efficiency of heat-exchangers in power plants. Conductance probes were fabricated, calibrated and tested, then placed in a horizontal test-section to detect the onset of slug flow. Conductance data were recorded by a digital oscilloscope, and analyzed to map out the pressure-temperature-velocity regime under which this flow persists.