What Insurance Adjusters and Inspectors Need to Know about Earthquake Damage Assessment
It’s always earthquake season. Are you prepared?
Amber Prom, PE, Director of Curriculum/Forensic Engineer
As professionals who study how buildings respond to seismic forces, we cannot look away from the devastation in Venezuela caused by the earthquakes on June 24th. Our hearts go out to the countless families affected, and to the rescue teams and communities still working through recovery.
If you’ve ever stood on a dock and felt the subtle sway beneath you, you already have a tiny taste of what the ground does during an earthquake — except instead of a gentle bob, imagine that dock is made of concrete, it weighs several million pounds, and it’s trying to shake a 40-story building off its foundation. Earthquakes are one of nature’s most humbling reminders that the earth we build on is very much alive.
For insurance adjusters sizing up a cracked foundation, contractors trying to understand why a building performed the way it did, or attorneys piecing together a timeline of damage, having a working knowledge of earthquake mechanics is genuinely useful. And unlike hail season or hurricane season, earthquake season doesn’t show up on a calendar. It’s every single day of the year, in California, the Midwest, or somewhere most people would never expect.
What Exactly Is an Earthquake?
The Earth’s outer shell, called the lithosphere, is broken into a series of massive slabs known as tectonic plates. These plates move constantly — albeit very slowly —grinding past, colliding with, and pulling away from one another along their boundaries. As the plates drift, movement produces planes of weakness in the rock called faults, and there are many faults throughout the subsurface rock volume. Luckily, most are old and dormant, and they are no longer building any strain energy; however, when stress builds up along these fault lines faster than the rock can quietly accommodate it, something must give. That “giving” usually comes in the form of a slip, resulting in an earthquake. An earthquake is a sudden release of energy that sends seismic waves radiating outward in all directions from the point of rupture, called the hypocenter or focus. The point on the earth’s surface directly above the hypocenter is the epicenter — the term most people have heard on the evening news.
Where Do Earthquakes Happen Most Often?
Globally, the lion’s share of seismic activity occurs along the “Ring of Fire,” a horseshoe-shaped belt encircling the Pacific Ocean that traces the boundaries of several major tectonic plates. Countries like Japan, Indonesia, Chile, and the Philippines sit squarely in this zone and experience some of the most frequent and powerful earthquakes on the planet.
In the United States, there are numerous faults throughout the country, but since they are dormant, most people associate seismic risk with California. The San Andreas Fault system is one of the most famous faults in the world. Oregon, Washington, and Alaska carry similar exposure. Together, the Pacific Coast states represent the highest concentration of seismic risk in the country. The Pacific Northwest faces a particularly sobering threat from the Cascadia Subduction Zone, a roughly 700-mile-long fault capable of producing magnitude 9.0+ megathrust earthquakes, the last of which occurred in January 1700.
But seismic hazard extends well beyond the West Coast:
- The New Madrid Seismic Zone, centered near the Missouri-Tennessee border, is one of the most active seismic zones east of the Rockies. The series of massive earthquakes in 1811–1812 it produced was powerful enough to temporarily reversed the flow of the Mississippi River.
- Charleston, South Carolina experienced a devastating earthquake in 1886.
- Oklahoma and Texas have seen a dramatic spike in seismic activity in recent decades, with some events tied to lubrication and activation of dormant, or less active faults, by energy industry operations.
These other areas may exhibit risk for rare, very large events or relatively frequent, minor events, but the takeaway: seismic risk in the U.S. is far more widespread than most people assume, which has direct implications for anyone in the property damage profession, regardless of where they are based.
How Earthquakes Damage Buildings
Here’s where it gets particularly relevant for anyone assessing property damage. Before we get to the dramatic stuff — collapsed chimneys, failed foundations, pancaked soft-story buildings — let’s start where most real-world earthquake inspections actually start: the cracks.
The very first thing an earthquake does to a building, even a modest one, is strain its brittle finishes. Materials like drywall, stucco, and plaster have limited flexibility, and when the ground shakes a building enough to skew the frame laterally, they crack. And they don’t crack just anywhere. The back-and-forth racking motion concentrates stress at the weakest points in the wall, which are the corners of doors, windows, and archways. If the shaking event is of sufficient strength and duration, the result is a telltale pattern of diagonal cracks radiating from the corners of those openings and at the corners of wall intersections.
In most cases, this is cosmetic damage. The wall is intact, the structure is sound, and a skilled finisher can have it looking brand new in an afternoon. The challenge is that diagonal cracking at door and window corners is not exclusive to earthquakes. Similar patterns can result from age and long-term settlement, thermal shrinkage, wind loads, and foundation movement. Distinguishing earthquake-caused damage from pre-existing conditions is one of the most common and consequential judgment calls a property assessor will make in a post-earthquake damage inspection. Getting that wrong in either direction has real consequences: missed earthquake damage leaves a policyholder undercompensated, while misattributing pre-existing cracks to a seismic event creates claims that shouldn’t exist. This is precisely why training and experience matter so much in earthquake damage assessment, even for what appears to be simple cosmetic damage.
Structural and Foundation Damage
When seismic intensity increases, the damage picture changes significantly. Seismic waves don’t push on a building or structure the way wind does — they move the ground beneath it. The foundation moves, and the rest of the structure, due to its own inertia, wants to stay put. This creates dynamic lateral forces that the structure must resist or absorb.
Several factors determine the severity of that demand:
- Earthquake magnitude and the distance from the epicenter
- Duration of shaking
- Local soil conditions: Soft soils, in particular saturated clays and loose sands, can amplify ground motion dramatically compared to hard rock, a phenomenon known as site amplification. Worse yet, saturated granular soils can become suspended enough to undergo liquefaction behave temporarily like a liquid, allowing foundations to sink, tilt, or otherwise distort due to the loss of soil bearing capacity. This is a geotechnical engineering concern that typically requires specialized investigation to predict and/or confirm that site characteristics are conducive to liquefaction.
Damage Patterns by Building Type
Structurally, damage patterns vary widely by building type.
- Unreinforced masonry buildings (brick structures without internal steel or concrete reinforcement) are notoriously brittle and prone to catastrophic failure in seismic events.
- Soft-story buildings, which feature a weak or open first floor (think apartments over a parking garage), are prone to “pancaking,” where the upper stories collapse onto the lower ones.
- Wood-frame structures generally perform better due to their geometry, natural frequency, and redundancy, though connections and anchorage details remain critical.
One of the least intuitive but most important concepts in earthquake damage assessment: the age of a building is often a more reliable indicator of seismic vulnerability than its outward appearance. A well-maintained older brick building can be a seismic disaster waiting to happen, while a less visually impressive modern structure built to current code may perform far better. This is exactly the kind of knowledge that separates a prepared damage assessor from one who is simply guessing.
How Engineers Design for Seismic Loads
You can’t stop an earthquake, and you can’t prevent a building from responding to one without substantial expense. So modern seismic engineering takes a different philosophical approach. Rather than designing structures to be infinitely strong or isolating their bases from ground motion, engineers design them to be intelligently ductile and protect life. The goal is a controlled, predictable response where the structure absorbs seismic energy through carefully designated yielding mechanisms rather than experiencing sudden, catastrophic failure. The building may experience significant cosmetic damage, but people will not be killed.
This philosophy is codified in standards like ASCE 7 (Minimum Design Loads for Buildings and Other Structures) and enforced through building codes like the International Building Code (IBC), which classify structures by a Seismic Design Category. This is an A through F classification based on the building’s occupancy and the seismic hazard at its location. Higher-risk buildings with higher occupancy and critical function, such as hospitals, fire stations, and emergency facilities, are held to stricter standards because they need to remain operational after an earthquake, not just standing.
Practically speaking, this translates into a wide toolkit of engineering strategies.
- Moment-resisting frames and shear walls are designed to flex and dissipate energy without collapsing.
- Base isolation systems are large, engineered bearings installed between the foundation and the structure. They decouple the building from the ground motion, allowing the earth to shake while the building moves far less dramatically.
- Tuned mass dampers are large counterweights often installed at the top of tall buildings. They swing in opposition to the building’s movement to counteract sway.
The Gap Between New Construction and Aging Infrastructure
Here’s the catch, though — and this is the part that matters most to those out there assessing property damage. All of those sophisticated engineering solutions are most commonly found in newer, larger, and higher-occupancy structures: the hospitals, the high-rises, the government buildings, the critical infrastructure. These buildings receive the most rigorous engineering attention, the most thorough peer review, and the most stringent inspections precisely because the consequences of their failure are catastrophic and public.
But the average residential home? A 1960s wood-frame ranch in the San Fernando Valley? A century-old brick duplex in St. Louis sitting atop the New Madrid Seismic Zone? Those structures were likely built before modern seismic code requirements and received no seismic upgrades since construction. The IBC and its predecessors have raised the bar for new construction significantly over the decades, but the existing building stock in this country is vast, aging, and in many cases woefully underprepared for seismic demands. And here is the reality for anyone in the property damage profession: the bulk of what you will be assessing after an earthquake is not the engineered high-rise that performed exactly as designed. It’s everyday structures —residential homes, small commercial buildings, older unreinforced masonry storefronts, and wood-frame apartments — where seismic engineering was an afterthought, if it was a thought at all. Understanding how and why those structures are vulnerable, what failure looks like in them, and how to distinguish earthquake damage from a lifetime of wear and tear is where the real skill in earthquake damage assessment lives.
What Qualified Earthquake Damage Assessments Require
An earthquake doesn’t care whether you’ve ever handled an earthquake claim before. When the ground moves — whether it’s a magnitude 6.0 rattling the suburbs of Los Angeles or a surprising magnitude 5.0 shaking the Mid-South — the claims come in, and carriers need qualified professionals who know what they’re looking at.
Even moderate earthquakes outside of California can cause real property damage: cracked foundations, dislodged chimneys, failed masonry veneers, shifted cripple walls, and compromised connections that aren’t visible to the untrained eye.
Most homeowners that experience an earthquake immediately do a visual assessment of their home for potential damage. Cracks in brittle finishes that have been there for years are often misdiagnosed as earthquake damage, and it will be your job to assess each of those properties and determine what was and was not caused by the recent shaking. Misidentifying pre-existing conditions as earthquake damage, or worse, missing actual structural damage, carries serious professional and financial consequences. This is why earthquake damage assessments require training, field experience, and in complex cases, the involvement of a forensic engineer who can provide scientifically backed reports and defensible findings.
California Earthquake Damage Assessment Certification
Haag developed our own version of the California Earthquake Damage Assessment Certification, a professional training course built specifically for insurance adjusters, contractors, property inspectors, and anyone involved in post-earthquake damage assessment. The certification satisfies California’s requirements for adjusting earthquake claims, but the training and knowledge it imparts applies to any earthquakes anywhere in the country. The course covers:
- Fundamentals of seismic events
- How ground motion translates into forces on the structure
- What damage patterns to look for across different building types and construction eras
- How to document and differentiate earthquake damage from pre-existing conditions
- When and how to engage a structural forensic engineer or other expert to support a complex claim
Catastrophe deployment doesn’t wait for you to get up to speed. Carriers and CAT teams prioritize certified adjusters and inspectors who are ready to deploy immediately. The Haag California Earthquake Damage Assessment Certification signals to employers and carriers alike that you are prepared, credentialed, and stand ready.
Unlike hail season or hurricane season, there is no off-season for earthquakes. The fault lines don’t take a break, the ground doesn’t send a warning, and the next event could happen tomorrow anywhere in the country. The only question is whether you’ll be ready when it happens.
To learn more about the California Earthquake Damage Assessment Certification and Haag’s full suite of professional training courses, visit haageducation.com.
Amber Prom, PE
Amber Prom, PE, is Director of Curriculum and a Forensic Engineer for Haag, a Salas O’Brien Company. Based near Denver, Ms. Prom is a Registered Professional Structural Engineer with 16 years’ experience in structural design, project management, forensic engineering, and engineering management/training. Amber previously worked as Professional Development Manager, Project Engineer/Technical Lead, and Principal Consultant for 8 years. She was responsible for training all new hires and providing continuing education/training for existing experts within the Civil/Structural and Building Consultant Divisions. She built this training program from the ground up for 100+ experts throughout the U.S. and Canada. As a Project Engineer/Principal Consultant, she conducted forensic engineering investigations related to building components which had failed, become damaged, did not operate/function as intended, or were constructed deficiently. She was also the Technical Lead for processes, including performing field investigations, documenting/photographing, equipment use, etc.
Ms. Prom’s previous experience also includes working as a Design Engineer, where she designed a multitude of industrial power plant elements electrical transformer containment areas and foundations, miscellaneous electrical buildings and foundations, 140-ft cantilevered stair tower, multi-level steel platforming, among many others. She was a Project Manager for commercial projects, including those in high seismic areas, hurricane-prone areas, and high snow-load regions.
Any opinions expressed herein are those of the author(s) and do not necessarily reflect those of Haag, a Salas O’Brien Company or subsidiaries.
