The 6.4 and 7.1 magnitude earthquakes that struck Ridgecrest and Trona, CA on July 4th and 5th, 2019, with thankfully low reports of critical injuries, reminded every one of us of the need for adequate earthquake preparation. But our geological experts talk of aftershocks and “quake swarms” also reminded us of a past temblor-related claim investigation case study from the other side of the country…
One year ago, Guardian Group, Inc.’s Property & Casualty forensic construction & engineering experts were called to the scene of an east coast residence to investigate alleged earthquake damage. The homeowner claimed that throughout the residence one could readily observe cracking to the interior gypsum wallboard – the result, he assumed and alleged, of earthquake damage.
When our earthquake expert researched the area, he discovered that an earthquake did, in fact, occur. Drawing upon seismic information in the Earthquake Archives, maintained by the U.S. Geological Survey, our experts confirmed a Richter magnitude 4.1 with an epicenter approximately 90 miles from the loss location.
Immediately dispatching to the scene, Guardian Group’s earthquake/forensic expert conducted a thorough site investigation. At the exterior, all facades were examined and photographed. No damage was detectable. The interior inspection, on the other hand, revealed multiple instances of apparent damage.
Observations included over a dozen instances of wall and ceiling cracks throughout the home and a crack in the concrete slab at the base of the home’s stairs. Water damage was evident on the kitchen ceiling, with the kitchen sitting just below the upper level bathroom. Additionally, a void was discovered between the wall and baseboard along the staircase, a void that also housed plenty of dust and debris.
Ultimately, despite all these seeming earthquake cracks and damages, the engineer from our Property & Casualty Group stated that the gathered evidence pointed to the contrary. His well-reasoned report clearly spelled out: 1) the impact of differential soil settlements and the connection between that and the crack discovered in the concrete slab, 2) expected shrinkage cracks in drywall compounds versus the type of cracks that appear as a result of earthquake movement, 3) the kitchen ceiling moisture as the result of some prior bathroom flooding or leakage incident, and 4) much of the damage cited by the homeowner predated the event, with accumulated dust and debris affirming his expert opinion. The report also verified that everything observed in the home was cosmetic only and that the structural integrity had never been compromised.