BOB HIRSHON (host):
Clues to quakes in caves. I’m Bob Hirshon and this is Science Update.
Drips of mineral rich water from cave ceilings form stalagmites that slowly grow from cave floors. Over thousands of years, these icicle-like formations silently record the history of the cave. In the Bulletin of the Seismological Society of America, University of Illinois geochemist Samuel Panno reports that stalagmites provide a record of earthquakes that happened thousands of years ago.
SAMUEL PANNO ( University of Illinois):
We collect the stalagmites from the cave and slice them in half the long way, and then open them up, basically like a book.
That reveals growth rings around a central axis, like tree rings. Shifts in the axis tell them when earthquakes hit. He says long range records of quakes going back tens of thousands of years will help scientists find patterns that could provide clues into when earthquakes will strike again. I’m Bob Hirshon, for AAAS, the science society.
Story by Bob Hirshon