Posted June 14, 2010, 9:40 PM.

The quake's magnitude was a preliminary 5.7 on the moment magnitude scale, and was centered near Ocotillo, California. It struck at 9:27pm.

Monday night's quake was the strongest aftershock to date of the 7.2 Sierra El Mayor quake on April 4th, and occurred on the Laguna Salada fault. The aftershock was to the northwest of the of the Easter Sunday earthquake, elsewhere on the fault line.

The quake was initially listed at magnitude 5.9 but later downgraded to 5.7.