Todd, no tunnel building, no M12 earthquake (which would take an asteroid/large meteor impact). Whether a M8 to M9 is possible farther north...well, near turn of 19th to 20th century (??) there was a M8+ earthquake that may have been on this trend (??) up in India that tossed boulder in the air. While the total number of M5+ aftershocks are probably normal, the number in the last few days from the Nicobar islands are not...in a long thread below I finally was able to post a plot of Don's list on my 3rd and 4th tries... there has been almost no decay in the number of aftershocks and probably energy release, and I'm rather sure this is not normal. I'd still like to see a more scientific explanation of what is going on, although Don's links are interesting. I would also like to hear the latest on where the main rupture really ended (this Nicobar area could be the north end, but there were a lot of large aftershocks all the way north to 14 deg...). John, Roger, Don, Canie, etc?