The recent earthquakes in Haiti and now in Chile I'm reminded of something I came across recently--the only recorded visual record of the 1906 San Francisco earthquake. No not sound, or photographic or film recording, I'm talking about the scientific recording that preceded the distinctive squiggly lines on a circular drum that we've all come to know.
This is how earthquakes were recorded around the time of the 1909 San Francisco earthquake. Typically the discs were brushed off and reused. This one wasn't, and is the only such record in existance. It's on display at the Mt. Hamilton observatory above San Jose, California.