• Mapping crustal structure across western North America with seismic refraction, velocity models, and gravity data to resolve crustal thickness variations and oceanic–continental transitions along the Coast Ranges, Great Valley, Sierra Nevada, and Basin-and-Range provinces. [1] [4] [6] [7]

• Spectral analyses of long-period surface waves to infer earthquake source mechanisms, testing unilateral fault models and moving-source concepts through amplitude and phase spectra of Love and Rayleigh waves. [2] [11] [12] [8]

• Surface-wave dispersion and azimuth/slowness analyses using oceanic and continental arrays to characterize upper-mantle structure and crustal heterogeneity in Pacific–California regions. [9] [18] [10]

• Seismicity studies correlating earthquake patterns with regional geology and major fault systems (San Andreas, Pacific Northwest), informing hazard assessments and tectonic models. [5] [17] [19] [20]

• Instrumentation and data-analysis paradigms, including close seismograph networks, high-magnification recordings, and early computer-based processing for epicenter determination and microearthquake studies. [14] [15] [16]