Answer
After the geyser erupts, the crevices fill with water and the cycle repeats. The filling and heating rates depend on the geyser's geological surroundings. If these rates roughly stay the same, then the time for the geyser to boil and erupt anew will be about the same, and the geyser will repeat its eruption on a Faithful schedule.
Work Step by Step
This is discussed on page 326.
