I've been noticing that lately large (>M6 quakes have come in pairs or triplets-where they occur maybe 1000 km or a couple thosand km apart, but still in the same general region-but they occur a few hours to a day or so apart. See the 2 pairs pasted below. There was another example a couple weeks ago, where there were 2 M7s and a M6.8 the same day. Also, there was the series of earthquakes from Alabama-Georgia Border, to 3 progressing S to N along the Mississipi river area to New Madrid zone to Illinois. I don't think these are explained by static stress changes (for the last mentioned series, quakes too small and widely separated, for the others, too far apart. I don't know if FFAs (fixed angular distances) can explain any of these. Maybe for the large ones it is some kind of twist put into a plate (???). One can call these coincidences, but does not seem like it to me. Chris

2003/06/15 19:24:34
51.65N 176.84E 33.0 6.5
RAT ISLANDS, ALEUTIAN ISLANDS

2003/06/16 22:08:01
55.54N 159.90E 172.8 6.9
KAMCHATKA PENINSULA, RUSSIA

2003/06/20 06:19:38
7.51S 71.64W 555.2 7.1
AMAZONAS, BRAZIL

2003/06/20 13:30:41
30.55S 71.37W 33.0 6.8
NEAR COAST OF CENTRAL CHILE