AEI provides seismic risk analysis of buildings in a Seismic Risk Assessment (SRA) report prepared in accordance with ASTM Standards E2026-16a and E2557-16a. The SRA report summarizes the risk of structural failure of a building due to the vibratory motion caused by the maximum probable design basis seismic event (DBE) that has a 10-percent chance of exceedance in a 50-year exposure period, or a 475-year return period.
AEI utilizes the Scenario Expected Loss Design Basis Earthquake (SEL-475) as the seismic loss damage ratio (commonly referred to as Probable Maximum Loss – PML). (SEL-475) is defined by ASTM E 2026-16a as the expected (mean) damage to a building resulting from a specified (scenario) seismic induced ground motion (peak ground acceleration). The specified peak ground acceleration is based on the probabilistic seismic hazard analyses developed from the USGS database. The ASTM has acknowledged in recently released guidance of ASTM 2557-16a, which suggests the use of the (SEL-475) estimate is used as the PML for CMBS transactions.
In accordance with ASTM E2026-16a, AEI also provides the Scenario Upper Loss (SUL-475), which represents the scenario loss that has a 10% probability of exceedance due to the specified ground motion of the scenario considered. Both Scenario Loss methods take into account various factors including but not limited to construction type, building age, site conditions, soil type, and proximity of the building to known potentially active faults.
The specific methodologies and the level of investigation (Level 0 through Level 3) are governed by the lender, but all include the following:
- Review of available geologic data, soils reports and structural drawings.
- Site visit for general assessment of the property, building(s), related facilities and general site characteristics. (Building Stability)
- Preliminary assessment of earthquake ground shaking, liquefaction potential and fault surface rupture potential based on readily available historical regional hazard data. (Site Stability)
- Preparation of a report including a list of general seismic deficiencies and preliminary estimate of facility earthquake damage loss based on empirical loss estimation methodologies. (Building Damageability)
The United States is divided into six seismic zones depending on hazard risk. Properties in seismically active areas have a higher risk of suffering significant damage in the event of a major earthquake. Knowing the seismic risk of your property is important to avoid future expenditures. Please review the map below to determine what seismic zone your property is in.
