CoolHandLuke wrote:I want to know more! I teach Earth science to sixth graders, even though my background is biology (not that I know much about that) but seismology fascinates me. I love finding seismograms through usgs or Iris or elsewhere, but reading them and understanding what is going on, past the basics, still mostly baffles me.
For my first question, the curriculum we are using comes with a seismogram of the 1964 Prince William Sound earthquake, taken in Washington state. The main quake only lasted for a few minutes, but the seismogram seems to be going crazy for several hours before you can see legible data again. What's going on there?
I was able to measure the p-s lag time of aftershocks, refer to their speeds, and come up with an estimated distance, which was really rewarding when it turned out to be fairly close to the actual distance.
Any other tips/resources/books to help a layperson understand seismology would be greatly appreciated!
Well, if you are using p-s lag and triangulation to estimate epicenter locations, that's advanced enough for an educator, imo. For seismology and seismic surveys, I've mostly only dealt with really low amplitude waveforms, so I'm only guessing for your particular case, but when you have a seismogram close to a serious business earthquake, you can record all kinds of crazy things. You'll record p wave first arrivals, p wave "multiples" which are akin to echoes, same thing for the s waves, converted waves, where p waves create s waves at significant geologic layers, and then there are all kinds of guided and surface waves scattering all over the place. That shouldn't last for an hour though. You might have just recorded a lot of "tremor" which is a kind of mono-frequency rumbling. I can't even remember what causes that to be honest. I think its like preshocks and aftershocks on a very small scale, and not technically cause by an earthquake.
My current job is kind of on the boring side now a days. No fieldwork. Just testing algorithms for seismic survey processing on a computer all day. Not nearly as cool as kicking half ton multimillion dollar instruments off boats.
But I'll check and see what kind of books look good. Mostly earthquake seismology? This book is more entertaining than educational, but its a fun read and one of my former coworkers is the main sidekick, Ted. https://www.amazon.com/Fieldwork-Christopher-Scholz/dp/0691012261