Seismic Risk | AEI Consultants

Seismic Risk Analysis

AEI provides a seismic risk analysis in a Seismic Loss (SL) report in accordance with ASTM Standards E2026-07 and E2557-07. The SL report summarizes the risk of structural failure due to the vibratory motion from the maximum probable earthquake event 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 (SELDBE) as the seismic loss damage ratio (commonly referred to as Probable Maximum Loss - PML). (SELDBE) is defined by ASTM E 2026-07 as the expected (mean) earthquake loss to a building resulting from a specified seismic induced ground motion (peak ground acceleration). The specified peak ground acceleration is based on the probabilistic seismic hazard analyses program FRISKSP-3.01b and the USGS database.The ASTM recently released guidance, ASTM 2557-07, indicating the use of the (SELDBE) estimate for CMBS transactions.

AEI can also provide the Scenario Upper Loss (SUL), which represents the scenario loss that has a 10% probability of exceedance due to the specified ground motion of the scenario considered. Both methods take into account various factors including construction type, site condition, soil type and location of the building to known faults.

The specific methodologies are governed by the lender, but all include the following:

Cursory review of available geologic and soils reports and drawings.

Site visit and general assessment of the property, building(s), related facilities and general site characteristics.

Preliminary assessment of earthquake ground shaking, liquefaction and fault surface rupture potential based on historical regional hazard data.

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.

The United States is divided into four 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.