The two events also had approximately the same type of faulting (focal mechanism). Such “doublets” rarely occur. The earthquakes are extremely deep (600 km or 360 miles); very few quakes strike deeper than these, because the rocks melt and do not behave in a brittle manner. At this site, the Nazca plate subducts beneath the South America plate at a rate of about 70 mm/yr (3 inches per year).
The events were probably widely felt but shaking was very light because of the extreme depth.
One can see from the map below that a large number of similarly deep (purple) quakes have struck during this century in about the same location. The focal mechanism suggests tensional stress, perhaps because the descending plate is bending at this depth.