The big one (M5.3) is normal, and is near a lake, which must be a reservoir. Shows near the upstream end of Lake Trinidad. Would be interesting to check the water levels on this. Extension leading to normal faulting earthquakes is expected in the Rio Grande Rift, which dies out into southern Colorado, but rather far to the west of this quake. But, maybe the rift splits up? (speculation)

OK, I'll take a quick look for water levels on this lake. High levels would make a quake more likely: both as increased pore pressure (if there is any connections down to the quake level) and as a vertical load: increased vertical load should favor normal faulting

Chris

• maps