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A 4.8 magnitude earthquake centered between New York and Philadelphia shook skyscrapers and suburbs across the northeastern U.S. for several seconds Friday morning, causing no major damage but startling millions of people in an area unaccustomed to such tremors. The same can’t be said for western Washington’s last major earthquake, the Nisqually earthquake which happened 23 years ago.

Where were you at 10:54 a.m. on Feb. 28, 2001? At that moment, there was a whole lotta shaking going on as the Nisqually Earthquake struck Western Washington.

The 6.8 magnitude quake was centered about 35 miles deep near Anderson Island in South Puget Sound and shook for just under a minute. The earthquake caused about $1 to 2 billion in damage, one person died from a heart attack, and about 400 were injured.

The most serious damage occurred near the epicenter or involved older unreinforced masonry or concrete buildings. Damages included parts of older downtown Seattle, the capitol building in Olympia, the Boeing Field runway, and the air traffic control tower at Seattle-Tacoma Airport.

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Elsewhere, the SR 99 Alaskan Way Viaduct in Seattle remained standing but suffered some support sagging and was deemed to fail in another earthquake. The Viaduct was eventually replaced with today’s tunnel which is designed to withstand a 9.0 magnitude earthquake.

The Seattle waterfront seawall also suffered damage and is in the process of being fully replaced.

Western Washington is prone to earthquakes, ranking number two in the lower 48 states behind California. The primary cause of these earthquakes is the subduction of the offshore Juan de Fuca tectonic plate under the North American plate. The Juan de Fuca plate is sliding under the North American plate at about 3.5 to 4.5 centimeters per year, placing Western Washington under growing pressure.

About 100 miles off the Pacific Northwest coast is the Cascadia Subduction Zone where the Juan de Fuca plate is sliding under the North American plate. This plate movement is also what generated the Cascade volcanoes and keeps them active in geologic time. The Cascadia Subduction Zone is part of the Pacific Ocean Ring of Fire where the majority of the globe’s biggest earthquakes and volcanic eruptions have occurred.

The subduction zone produces three types of earthquakes in our region. The big ones are rare megathrust events such as the Cascadia earthquake, the last to occur on January 26, 1700, and occur about every 300 to 500 years. The other types include shallow North American plate events and deep intra-slab events within the subsiding Juan de Fuca plate. This last type involved the Nisqually quake as well as the April 29, 1965, and April 13, 1949 (both magnitude 6.7) earthquakes in Western Washington.

Earthquakes are no-notice events. Yet today, an early earthquake warning system is in place named “ShakeAlert.” This system sends alerts to wireless devices, giving citizens critical seconds of lead time to prepare and take action before the shaking gets started.

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Created by the U.S. Geological Survey (USGS), this system uses a network of earthquake sensors throughout the West Coast that can detect a quake and provide information such as the location, magnitude, and expected duration via your wireless device as well as many media mediums like TV, radio and the internet.

You can get ready for earthquakes in advance. Remember to drop, cover and hold on when an earthquake starts. You can practice this safety technique with your family.

In addition, make an emergency plan and protect your home. Also include a communication plan in case the quake strikes when your family is separated at work, school or on the road.

Visit for all your earthquake preparedness guidelines, including what to do if the earthquake strikes while sleeping in bed, driving a car, or outdoors. also offers earthquake readiness guidelines along with many other local agencies and organizations.

This anniversary of the Nisqually earthquake gives all of us a reminder that Western Washington is earthquake country and that we need to prepare in advance so we are ready when the ground shakes unannounced.

Editors note: This piece originally was published on Wednesday, Feb. 28. It has been updated and republished multiple times since then.

Contributing: The Associated Press

Ted Buehner is a meteorologist for ³ÉÈËXÕ¾ Newsradio.