A 7.7 magnitude earthquake rattled much of Southeast Asia on Friday, flattening skyscrapers and leaving more than 1,000 people dead from Myanmar to Thailand.

Startled residents were evacuated down staircases of high-rise condominiums and hotels in Bangkok. In Myanmar's Naypyitaw, the quake damaged religious shrines and some homes.

Distances from the stations to the earthquake are estimated from the difference between P and S wave arrival times: You have just figured out how far your seismograph is from the epicenter and how ...