California residents all know (or think) the “big one” – a major earthquake – will happen, whether sooner or later, but it will happen. Some harbingers of doom suggest that San Francisco and Los Angeles will become one big (shattered) city.
Last week’s catastrophic 7.0 quake that shook parts of Alaska, followed by more than 230 small earthquakes Friday, certainly made those predictions even starker and closer to home.
According to the US Geological Survey, the quake knocked out power, ripped open roads and splintered buildings near Anchorage, second only to the destructive 9.2 quake in 1964 – the largest in US history.
All 50 states, five U.S. territories and the District of Columbia are at some risk for earthquakes. Earthquakes can occur at any time of the year.
For millions of years, the forces of plate tectonics have shaped the earth, as the huge plates that form the earth’s surface slowly move over, under and past each other. At times, the movement is gradual. At other times, the plates are fused together, unable to release accumulated energy. When the accumulated energy grows great enough, the plates break free.
Earthquake shaking can cause the water pressure to increase to the point where the soil particles can readily move with respect to each other.
The primary dangers to workers result from:
- Being struck by structural components or furnishings;
- Inadequately secured stored materials;
- Burns resulting from building fires resulting from gas leaks or electrical shorts; or
- Exposure to chemicals released from stored or process chemicals.
Many of the hazards to workers both during and following an earthquake are predictable and may be reduced through hazard identification, planning, and mitigation.
The highest hazard areas are concentrated in regions of man-made landfill, especially fill that was put in place many decades ago in areas that were once submerged. These types of areas are found in San Francisco, Oakland, and Alameda Island, as well as other places around San Francisco Bay.
Other potentially hazardous areas include larger stream channels, which produce the loose young soils that are particularly susceptible to liquefaction.
How prepared are you in the event of an earthquake?
OSHA’s preparedness and response pages provide information on hazards that earthquake causes, earthquake preparedness, and precautions that workers and employers should take after an earthquake has occurred.
The USGS’s Hazard Preparedness pages have many resources to prepare you for natural disasters.