The series ``Storing nuclear waste'' [beginning June 24] pointed out the geological and political problems involved in selecting a US waste repository. As a professional geologist in worldwide underground and surface mining, I believe the sites the DOE has selected are poor choices because: The layered basalt pile underlying the Hanford, Wash., area is saturated with migrating ground water, is adjacent to recent volcanism (Mt. St. Helens), and is close to the north-south line of semiactive volcanoes and active faulting along the Pacific coast.
The Yucca Mt. Nevada site is in the geologically active Great Basin region of the Western US where faulting and earthquakes are common. Also, the fairly recent layered volcanic rocks in the site area are not impervious and are of variable competency.
The Texas sites in salt domes are poor choices. Salt is the most soluble rock formation and could collapse after water attack from adjacent aquifers or from migrating oil and/or gas in peripheral areas.
There are sites that are not subject to earthquake faults, volcanic activity, and migrating ground water and would be stable for millions of years. These are the pre-Cambrian (2 billion-plus-year-old) rocks that form the underlying core of the North American Continent outcrop in the north-central states along the Canadian border. These ancient granitic and metamorphic rocks are far from volcanic centers and active faulting, and underground the rocks are dry and do not collapse. Glenn C. Waterman Bainbridge Island, Wash.
Congratulations on the series ``Inside Iran.'' I was amazed by the acceptance and kindness shown to the author by the Iranians, considering that she was a woman and an American as well. Perhaps it is true that an enemy is just a friend you have yet to meet. Elizabeth Asbury Atlanta Letters are welcome. Only a selection can be published and none individually acknowledged. All are subject to condensation. Please address letters to ``readers write.''