The geologist Thomas Jaggar died at the age of 81. Here is all you want to know, and more!
Biography - A Short Wiki
Volcanologist and founder of the Hawaiian Volcano Observatory who studied volcanic eruption in one of the most geologically active zones. He was a longtime professor at the University of Hawaii and was a Fellow of the American Academy of Arts and Sciences.
He was married to Isabel Maydwell, his former co-worker.