Using the seismic reading received at station 1 only, an observer would be able to determine

Answer

Neither the distance nor the direction of the epicenter from station 1

Explanation

A single seismic reading received at station 1 only will tell the observer that the ground shook at that location and the intensity. Without other data  and information, the observer cannot make any other meaningful conclusions. A minimum of three seismograph stations are required before an observer can determine/ conclude meaningful results.