Hi Chris. Dr. Sieh recognized that quakes occur in pairs sometime ago in certain areas. If I remember correctly he did give a warning for the Sumatra area, but couldn’t give the time of the quake. Take Care…Don in creepy town

“Douglas A. Wiens, Ph.D., professor of earth and planetary sciences at Washington University in St. Louis, has seismic wave evidence that many deep earthquakes in the Tonga area occur at the same spot repeatedly and often occur in pairs.”

“Realizing he would never solve the prediction puzzle in California, Dr. Sieh turned his attention a decade ago to faults off the coast of Sumatra.”

“His focus is on a patch of ocean floor a few hundred miles south of Sunday's earthquake.”

“Both areas are part of a vast subduction zone, where a huge block of the earth's crust slides under the Indonesian archipelago.”

“By dating mortality patterns in coral reefs affected by fault motions and tsunamis, Dr. Sieh determined that large earthquakes occur regionally, in pairs, every 230 years or so. In 1797 there was a magnitude 8.2 quake; in 1833 a magnitude 8.7 or bigger quake occurred. There was a cluster in the 1500's and one in the 1300's.”

"We are coming up on the beginning of the next cycle," Dr. Sieh said. "In the last four years, a number of smaller quakes have been flirting with these larger locked patches."

“For example, in June 2000, a quake of magnitude 7.0 was felt in Singapore. A 7.4 temblor in 2002, under Simeulue Island, off the northwestern coast of Sumatra, may have been a foreshock for Sunday's quake.”

“A second very large earthquake in the same offshore area would not come as a surprise, Dr. Sieh said. But it could be decades away.”

Tonga Area

Sumatra