Earth Quake in PortlandEarth Quake in Portland

By Michael ZaraBy Michael Zara

January 15 2003January 15 2003

Two earthquakes with magnitudes of Two earthquakes with magnitudes of 5.3 & 5.5 struck the Portland area.5.3 & 5.5 struck the Portland area.

The epicenters were located on the sea The epicenters were located on the sea floorfloor

The quake did not cause a tsunami or The quake did not cause a tsunami or tidal wave. tidal wave.

If these earthquakes had of occurred o If these earthquakes had of occurred o land, they would have done land, they would have done considerable damage.considerable damage.

Epicenters for QuakeEpicenters for Quake

Along Blanco fracture zone (FZ)Along Blanco fracture zone (FZ) Blanco FZ is located next to the Blanco FZ is located next to the

Cascadia subduction system.Cascadia subduction system. Past quakes on this zone have Past quakes on this zone have

exceeded 9.0 on the Richter exceeded 9.0 on the Richter Magnitude (RM) scale Magnitude (RM) scale

Quakes this big (>RM9.0) happen Quakes this big (>RM9.0) happen every 300 yrs, the last one being in every 300 yrs, the last one being in the 1700’s.the 1700’s.

Oregon State Department Oregon State Department of Geology suggestions for of Geology suggestions for dealing with earthquakesdealing with earthquakes Know how to protect your self by Know how to protect your self by

ducking under furniture or finding a ducking under furniture or finding a safe area.safe area.

Prepare a 72 hr emergency kit.Prepare a 72 hr emergency kit. Have a plan for communication with Have a plan for communication with

other family members if separated.other family members if separated. Know how to evacuate from coastal Know how to evacuate from coastal

areasareas

W. W. NortonW. W. Norton

Fig. 09.18aFig. 09.18a

W. W. NortonW. W. Norton