The Cascadia subduction zone runs offshore from Northern California through British Columbia. Major Cascadia events occur on the order of every 200–500 years; the last full-margin rupture was 1700. Oregon sits squarely within the exposure zone, with the I-5 corridor — Portland, Salem, Eugene — facing the most concentrated risk. For a condo buyer, the practical question is what the master policy covers, what the building's construction era implies for seismic resilience, and what your personal loss-assessment coverage needs to absorb if a major event occurs.

What Oregon law requires (and does not)

ORS 100.435 (condos) and ORS 94.675 (HOAs) require associations to maintain all-risk property insurance covering common elements and liability insurance in reasonable amounts. The statutes do not require:

• Earthquake-specific coverage
• Seismic evaluations of existing buildings
• Retrofits of pre-modern-code construction
• Disclosure of seismic risk on resale

Earthquake coverage is a market decision, not a statutory requirement. And — given the cost — many Oregon associations decline it.

Reading the master-policy declarations page for earthquake

Three patterns to look for:

Earthquake explicitly excluded. Most common. The master policy covers fire, water damage, theft, liability — but excludes earthquake. The exclusions endorsement will spell this out. Owners bear personal exposure for any uninsured association loss assessment that follows a seismic event.

Earthquake covered by separate endorsement. Some associations carry an earthquake rider. Read the deductible (often 5–15 percent of insured value, much higher than standard perils), the coverage limits (often capped well below standard property coverage), and the named-event provisions. A 15-percent deductible on a $50 million building is $7.5 million the association must absorb before insurance pays — which translates to substantial per-unit loss assessment.

Earthquake covered by separate standalone policy. Less common but cleaner. The association maintains a separate earthquake policy in addition to the all-risk master. Read this policy independently — the deductible, limits, and exclusions structure can differ from the standard master.

Construction era and seismic resilience

Oregon building codes have evolved meaningfully over time. Buildings constructed under more recent codes carry different seismic resilience than older stock. Rough generations to keep in mind:

• Pre-1970s. Predates substantial seismic code requirements. Older brick and masonry construction in particular carries higher unreinforced-masonry exposure.
• 1970s through early 1990s. Improved but still under earlier seismic provisions. Some retrofits may have been done voluntarily; most have not.
• Mid-1990s onward. Stricter seismic provisions. Buildings constructed under these codes generally carry better seismic resilience.
• Post-2010 era. Modern seismic codes with performance-based design increasingly used in larger projects.

None of this is statutorily disclosed. A buyer interested in seismic resilience should request:

• Any voluntary seismic evaluation report the board has commissioned
• The original construction date and any major retrofit history
• The construction type (wood frame, steel frame, concrete, unreinforced masonry)
• The master policy's earthquake treatment

Loss assessment and the HO-6 sizing question

The most likely seismic exposure for a unit owner is not the unit itself — it's the loss assessment that follows when an event causes association losses exceeding insurance. Even a moderate event can generate per-unit loss assessments of $5,000–$50,000 or more depending on building damage, deductibles, and uncovered losses.

For your HO-6:

• Size loss-assessment coverage against realistic post-event exposure
• Confirm the policy covers earthquake-driven loss assessment specifically (some exclude it)
• Consider personal earthquake coverage if the association has none
• Discuss with your agent how loss-assessment coverage interacts with master-policy earthquake riders

What CondoSignal surfaces

We pull the master-policy declarations page, exclusions endorsement, any voluntary seismic evaluation reports, construction-era documentation, and recent claim history into a single state-specific risk summary. We flag earthquake exclusions, surplus-lines placements, and seismic-related discussions in board minutes. The goal is to give Oregon buyers a focused conversation to take to their lender, insurance agent, and counsel before closing — particularly around the loss-assessment exposure that catches owners off-guard when seismic events do occur.