Hi All. Here is another article about silent subduction quakes. This one however killed a number of people. Take Care…Don in creepy town.

Coastal inhabitants can be educated to run to higher ground when they feel the land shake from an earthquake. But in certain tragic cases, such as the 1992 Nicaragua tsunami that killed 170 people and left 13,000 homeless, residents fell only a minor tremor, or even none at all, and assume there is no danger. An estimated 5 to 10 percent of tsunami-causing earthquakes are of this particularly hazardous breed—so-called silent earthquakes, first described by Hiroo Kanamori of the California Institute of Technology.

In the latest Nicaragua event, the short waves that produce the characteristic rumbling of an earthquake—and that die out quickly as they spread out from the epicenter—never made it from the quake's offshore origin to the mainland. Longer waves did reach the coast, but they hardly shook the ground. What is more, standard seismometers, which record only seismic waves with periods less than 20 seconds, missed most of these longer waves. Kanamori argued that the Nicaragua quake was actually five times greater than its assigned magnitude of 7.0 because these low-frequency waves had been ignored. The Nicaragua event made it abundantly clear that broadband seismometers sensitive to low-frequency waves must be linked to warning systems to forecast the true potential tsunami danger. -

• Silent Quake