This article from my local news station, located in Seattle, talks about recent swarms of earthquakes in Yellowstone. Earthquake swarms aren’t all that unusual there, but what fascinated me was the last three paragraphs:
“Smith traced the three recent earthquake swarms to the Hebgen Lake quake [in 1959 — my time traveling hero’s earthquake].
‘These are a really related,’ he said.
‘We think that much of the seismicity is still aftershocks from that event in 1959. It can go on for hundreds of years.'”