[TherapyforGlencross]

Originally Posted by MRCboicgy

I was reading the USGS summary about this one, and - if I understand it right - instead of having a true epicenter, it was really a 200 km by 20 km slip
https://earthquake.usgs.gov/earthqua...pn9s/executive

This is common on strike slip faults. In simplicity, this is a horizontal displacement. Epicentres are usually referring to above the focus which in this case is above the horizontal displacement. It’s just explaining how it’s a large but shallow earthquake.