Portland Earthquake Maps Guide

Updated 10/2024.

Portland does get its fair share of earthquakes, as does Oregon overall, but our state experiences fewer than any other West Coast State. There’s also good news for the future. Geologists are getting better at understanding, mapping, and predicting seismic activity. Maps also continue to improve, helping us stay better prepared for disasters by showing where resources and hazards are and highlighting data we can use to assess structural risks to homes and properties.

These Portland earthquake maps are worth reviewing before you buy a home.

What is the Earthquake Risk in Portland?

For the frequency of quakes, Oregon came in 10th nationwide in 2023. California and Alaska top the list, and Washington comes in at number 7, making Oregon the safest West Coast state. Notably, many states in the top 10 list aren’t located on the Pacific Ocean, so the West Coast isn’t the only threat; regardless, the coast is prone to them.

Why? Oregon sits along the Pacific Rim, an area roughly outlining most of the Pacific Ocean. The area is also called the Ring of Fire due to the frequency of volcanoes and earthquakes. Portland sits on the edge of the Pacific Rim. According to some sources, the city and its surrounding region are Oregon’s most seismically active areas.

Portland also sits on the Cascadia Subduction Zone (CSZ), a fault that runs from northern California to Vancouver Island, Canada. Cascadia earthquakes are big, and we’re expected to have a new one soon if predictions are correct. The earthquakes occur every 300-500 years, and the last was 324 years ago. The 9.0 quake spanned Northern California to British Columbia.

Even if the next quake’s magnitude is a more conservative estimation of 7.0 or 8.0, anything over 7.0 can cause extensive damage, so it’s good to be prepared. Portland still has over 160,000 homes built before 1974, predating statewide building codes. Since codes were enacted, homes built after 1993 are the most likely to withstand earthquakes.

Fortunately, most homes in Portland are not built from unreinforced masonry; in fact, most Portland homes are made from wood, which is very earthquake resistant. Still, many homes built before seismic standards were put in place in 1993 could slide off their foundations in the event of an earthquake. The good news is that homes can be retrofitted to be more resilient to earthquakes. Read more here on our blog.

Top 6 Portland, Oregon Earthquake Maps

Note: As you go through this article, click on the header links to reference the maps.

1. USGS Map – Latest USA Earthquakes

If you are fascinated by seismic activity, this live US Geological Survey map provides up-to-the-minute information about earthquakes around the globe. They appear as dots on the map, and the colors indicate how long ago they occurred.

The map can show a history of all earthquakes for the past thirty days; beyond that, there would be too much data for most home computers to display, a good reminder that earthquakes are happening all the time around the world. On the day of this writing, three occurred over 5.0 worldwide.

2. USGS Map – National Seismic Hazard Model (NSHM)

Though earthquake historical data is massive, the USGS managed to join it with other seismic studies and new data-collection tech to create a new map showing where damaging earthquakes are likely to occur. The results are pretty humbling, with 75% of the US at risk of shaking. This map aims to mitigate financial losses from quakes by integrating what scientists have learned about earthquake sources, crustal deformation, active faulting, and ground shaking.

3. USGS Map – Quaternary Faults Map

This map shows where earthquakes are likely to occur around the world. California appears to be one solid fault line from a distance, but Oregon has a few, too. Zoom in on Portland to see the fault line from Lake Oswego to Northwest Portland!

Quaternary Faults appeared less than 1.6 million years ago — relatively recently in geologic time. While the Portland fault is technically active, geologic time offers some comfort: An active fault is one that has experienced movement in the past 10,000 years.

4. City of Portland Geologic Hazards Map

The Latest Earthquake maps and Faults maps are interesting, but they don’t show what hazards occur in any given area. According to USGS, an earthquake hazard is “anything associated with an earthquake that may affect the normal activities of people. This includes surface faulting, ground shaking, landslide, liquefaction, tectonic deformation, tsunamis, and seiches [a type of standing wave that occurs in closed bodies of water.”

To learn about earthquakes that can – and eventually will – happen in Portland, as well as other geologic hazards like landslides, our real estate agents turn to the Portland Geologic Hazards Map, created by the city’s Bureau of Planning and Sustainability. This map shows two significant types of information:

• The intensity of two earthquakes that are likely to hit Portland soon. Using the Layers panel, users can toggle between a Cascadia Subduction Zone earthquake or a Portland Hills Fault earthquake. The orange-red shading on the map indicates the intensity of shaking; most of Portland would experience Very Strong to Severe effects if either one of these earthquakes were to happen!
• Landslide deposits and steep slopes. Hint: It’s easier to see these areas if you uncheck the “Earthquake Hazards” box in the Layers panel. The irregularly shaped areas filled with triangles are zones where landslides have happened, leaving behind deposits. Landslides are more likely in the event of an earthquake or heavy rainstorm, but they can occur anytime and are incredibly destructive to property. Be sure to consult with a geoengineer before buying a home in an area affected by landslides!

5. Portland, Oregon’s Unreinforced Masonry Buildings Map

This is another map by the Bureau of Planning and Sustainability. It shows all the buildings in Portland that could be dangerous when the ground shakes. Unreinforced Masonry Buildings, or URMs, are made of bricks or cinderblocks held together by mortar that crumbles easily under seismic stress. Newer masonry buildings in Portland are reinforced by steel and bolted to their foundations; those built before 1960 were not. According to the City of Portland, “URMs are more prone to sustain significant damage, which may include partial or total collapse, during seismic events .” Knowing where URMs are in Portland is essential for residents and visitors alike — they are not places you want to be around when an earthquake hits!

This map has two layers: Colored squares showing URMs and color shades showing the earthquake hazard beneath those buildings. The Legend shows what the colors mean, with the earthquake hazard displayed as “low” to “very high” liquefaction.

What is “liquefaction”? Good question. When soil or sand is saturated by water and subject to shaking in an earthquake, it starts acting like a fluid. Think of when you stand on the beach in wet sand and wiggle your feet. That’s not an ideal substance to build or stand on, especially when the walls are not reinforced.

6. Your Own Neighborhood Earthquake Map

There’s yet another type of earthquake map, but this one relies on something other than geological information. We’re talking about a DIY map that shows vital information about resources and risks at the neighborhood level.

The Map Your Neighborhood program is a grassroots effort to help Portland be more prepared for disaster. Neighborhood Emergency Teams (NETs) are usually the people who create these maps, and they don’t publish the maps online for privacy reasons. Portland’s NETs are made of volunteers who have gone through a training program designed by FEMA. They meet regularly and participate in simulations to be prepared for disasters like earthquakes.

Map Your Neighborhood is a way to identify things that need to be found quickly in case of an earthquake, such as gas shut-off valves, or special hazards like URMs. These maps also show which neighbors have special needs and might be unable to help themselves in an emergency.

Does your neighborhood or the neighborhood where you’re considering buying a home participate in Map Your Neighborhood? Find out by looking up your Neighborhood Emergency Team leader. Emergency preparedness is more than a great idea; it’s also an easy way to meet the neighbors.

Work with a Local Expert

If you are selling or buying a home, having a local Realtor on your side is a powerful asset. Our long history in Portland helps us spot factors that can put a Portland home at greater risk, such as the time when the home was built and the type of construction that was used. We can also spot if an area has a history of disasters that affect the home’s price.

Our top 1% Portland real estate team has been advising buyers and sellers for over 20 years. We’d love to connect with you today, give us a call or chat with the bot on this site.