BY PETER J. SMITH
Department of Earth Sciences
Open University
Milton Keynes, U.K.
" Because there has been no great earthquake in the Shumagin Islands area of the Aleutian Trench since at least 1917, the region is regarded as having high seismic potentiaL However, no strain accumulation was detected during 1980-87, suggesting that the seismic danger has been overestimated.
M. Lisowaki, J.C. Strange, W.H. Prescott, W.K. Gross, “Absence of strain accumulation in the Shumagin seismic gap, Alaska, 1980-1987,” Journal of Geophysical Rcsearch, 93 (B7), 7909-22, 10 July 1988.
" Cretaceous-’Tertiary (K-T) boundary clays in Europe and New Zealand are enriched not only with iridium but also with soot. The meteorite impact that supposedly caused the K-T mass extinctions apparently also initiated a global fire.
W.S. Wolbach, L. Gilmour, E. Anders, CJ. Orth, R.H. Brooks, “Global fire at the Cretaceous-Terrtiary boundary,” Nature, 334 (6184), 666-9,25 August 1988.
" In the rift ...
