Theoretical and Computation Contributions by J. M. Lees

I have written several papers about computational aspects of seismology, time series analysis, GIS, mapping, interactive graphics and other computations. Most of my software is freely available for download.

Published papers

Lees, J.M., (1998). Multiplet analysis at Coso Geothermal. Bull. Seismol. Soc. Am., 88(5): 1127-1143.

Lees, J.M., (2000). Geotouch: Software for Three and Four Dimensional GIS in the Earth Sciences. Computers & Geosciences, 26(7): 751-761.

Lees, J.M. and Wu, H., (2000). Poisson's ratio and porosity at Coso Geothermal Area, California Iversen, E.S. and Lees, J.M., (1996). A statistical Technique for validating velocity models . Bull. Seismol. Soc. Am., 86(6): 1853-1862.

Wave Propagation

Wu, H. and Lees, J.M., (1999). Cartesian Parameterization of Anisotropic traveltime tomography. Geophys. J. Int., 137(1): 64-80.

Wu, H. and Lees, J.M., (1997). Boundary conditions on a finite grid: Applications with pseudo-spectral wave propagation. Geophysics, 62(5): 1544-1555.

Signal Processing

Mann, M.E. and Lees, J.M., (1996). Robust estimation of background noise and signal detection in climatic time series. Climate Change, 33: 409-445.

Lees, J.M. and Park, J., (1995). Multiple-taper spectral analysis: A stand-alone C-subroutine. Computers & Geology, 21(2): 199-236.

Lees, J.M., (1995). Reshaping spectrum estimates by removing periodic noise: application to seismic spectral ratios. Geophys. Res. Lett., 22(4): 513-516.

R-code located on CRAN

Lees, J. M. (2008), RSEIS: Multiple interactive codes to analyze seismic data, via, spectrum analysis, wavelet transforms, particle motion, hodograms. DOWNLOAD

Lees, J. M. (2008), GEOmap: Topographic and Geologic Mapping. http://rh-mirror.linux.iastate.edu/CRAN/. DOWNLOAD

Lees, J. M. (2008), RTOMO: Visualization for seismic tomography. http://rh-mirror.linux.iastate.edu/CRAN/. DOWNLOAD

Lees, J.M., (2007). ProfessR: Grades Setting and Exam Maker, Comprehensive R Archive Network, pp. Description Programs to determine student grades and create examinations from Question banks. Programs will create numerous multiple choice exams, randomly shuffled, for different versions of same question list. DOWNLOAD

Lees, J.M., (2007). RFOC: Graphics for Spherical Distributions and Earthquake Focal Mechanisms, Comprehensive R Archive Network, pp. Graphics for statistics on a sphere, as applied to geological fault data, crystalogaphy, earthquake focal mechanisms, radiation patterns, ternary plots and geographical/geological maps. DOWNLOAD

Lees, J.M., (2007). RPMG:Graphical User Interface (GUI) for interactive R analysis sessions, Comprehensive R Archive Network, pp. Poor Man's Gui: create interactive R analysis sessions. DOWNLOAD

Lees, J.M., (2007). zoeppritz: Zoeppritz Equations, Comprehensive R Archive Network, pp. Calculate and plot scattering matrix coefficients for plane waves at interface. DOWNLOAD

Thompson, E.M. and Lees, J.M., (2007). Rsac:Seismic analysis tools in R, Comprehensive R Archive Network, pp. The functions in this package are mostly designed to reproduce the most commonly used functions in the LLNL software Seismic Analysis Code (SAC, http://www.llnl.gov/sac/). This includes reading standard binary SAC (and also SEGY) files, plotting arrays of seismic recordings (the "SAC" plotting style), filtering (high pass, lowpass, and bandpass IIR filters), integration, differentiation, instrument deconvolution. DOWNLOAD