It might be that Sophie could have sensed the P wave arrival before the more destructive S wave.
A quick way to determine the distance from a location to the origin of a seismic wave less than 200 km away is to take the difference in arrival time of the P wave and the S wave in seconds and multiply by 8 kilometers per second. Modern seismic arrays use more complicated earthquake location techniques
http://en.wikipedia.org/wiki/Seismic_waveAssumminig the 8km/second and the epicentre of the Eureka Earthquake was 70km away
http://neic.usgs.gov/neis/bulletin/neic_rha1.htmlthen the time difference would be around 9 seconds between the P wave and S wave arrival times.