PORTLAND -- Sunday's night 3.3 earthquake in Sherwood, Ore. may have been small, but it was a big reminder that earthquakes can happen anytime in the Northwest.
Over the past two weeks, Oregon and Washington have experienced more than 130 earthquakes, according to the Pacific Northwest Seismic Network.
Experts said that's about normal. Most earthquakes are so small you can't feel them. But over the years, there have been sizable earthquakes in the Pacific Northwest.
On February 28, 2001 a 6.9 magnitude earthquake rattled the Olympia area. It damaged several buildings, including the state capitol.
The "Spring Break Quake" of 1993 hit on March 25th. It was a 5.6 magnitude earthquake, centered in Scotts Mills, 35 miles south of Portland.
In September 1993, a pair of earthquakes struck Klamath Falls. They had magnitudes of 5.9 and 6.0.
The deadliest earthquake in Northwest history was the 1964 "Great Alaska Quake." It was a 9.2 magnitude earthquake, the second largest ever recorded.
Experts have predicted that "The Big One" is still to come. It would likely reach a magnitude 9.0 or greater and have devastating consequences on the entire Pacific Northwest.
"We're talking about two to four minutes of shaking. It would shake up to ten minutes," said Althea Rizzo of Oregon Emergency Management. "We don't know when it is going to happen. We just know that it will."