I received an email notification this afternoon that a Magnitude 3.5 earthquake occurred east southeast of Nelsonville, Ohio just before 1:00 pm local time. My heligraph has been very noisy so I couldn’t really see any signal even though the epicenter was only 79 miles south of Millersburg where I am located. When I zoomed in on the trace though I could see an excursion at about the right time. Just to be sure I checked a nearby helicorder located at Kent State University Branch campus in New Philadelphia, one of the OhioSeis network stations. It showed the first arrival at about 20 seconds past 18:00 UTC, the same as mine. There were 373 felt reports by mid afternoon mostly in southeastern Ohio..
Postscript (April 27, 2014) :
In an email exchange with another amateur seismologist, he had included a link to additional information on using the AmaSeis software. As I read some of the entries I found an article on analyzing local events so I applied it to this event in Nelsonville, only 79 miles south of my seismograph. One of the characteristics of local earthquakes is that they have a higher frequency content than more distant teleseismic events. These can be extracted by using a high pass filter on the signal. Following the lead of the article, I applied a 1.2 second high-pass filter twice to the Nelsonville signal with the results shown below. Impressive!