Endo, E. T., Murray, T. L., and Power, J. A., 1996, A comparison of preeruption real-time seismic amplitude measurements for eruptions at Mount St. Helens, Redoubt Volcano, Mount Spurr, and Mount Pinatubo: in Newhall, C. G. and Punongbayan, R. S., (eds.), Fire and mud: eruptions and lahars of Mount Pinatubo, Philippines, Quezon City and Seattle, WA, Philippine Institute of Volcanology and Seismology and University of Washington Press, p. 233-247.