Shaky Landings

When a recent earthquake damaged the control tower at Seattle-Tacoma Airport, affecting flights into the Pacific Northwest, planes were diverted to other West Coast airports. In the Bay Area, where some passengers eventually landed and others were prevented from taking off, the disaster brought home the need for understanding what happens to airports in earthquakes—not only those close to the epicenter, which may be damaged, but those farther away which may assume an unexpected reliever role. A new Association of Bay Area Governments (ABAG) report, Don't Wing It: Airports and Bay Area Earthquakes, looks at these concerns.

Since the 1989 Loma Prieta earthquake, passenger terminals at all three Bay Area airports have been retrofitted to improve safety, and the new international terminal at San Francisco International Airport (SFO) was designed to withstand a major temblor. However, control towers at all three airports would probably sustain enough damage to send air traffic controllers to temporary emergency quarters. The newest tower, at San Jose International Airport is only 8 years old, but the tower at Oakland International Airport is almost 40 years old and is scheduled for replacement.

Airport runways would also have significant damage. According to ABAG reports, liquefaction, in which soil loses its solidity and allows objects to sink or topple over, would pose the greatest problem for runways. At SFO, where runways are built mainly on fill, portions of the runways could sink a foot or more under some quake scenarios. Other problems include power and communications disruptions, and impacts on the "land-side" transportation systems serving the airports.

Some of the damage can be avoided. Just as passenger terminals have been strengthened, towers can be retrofitted or rebuilt. New construction techniques will help runways to stretch instead of rupturing or buckling during a quake.

However, emergency planning is also important. In Seattle, a good emergency plan sent air traffic controllers to a temporary control center where they resumed limited operation within hours. The Federal Aviation Administration guidelines for the Bay Area call for regional air traffic facilities in Oakland and Fremont to coordinate emergency operations, but airlines and pilots have the final decision on where to land. In October 2000, ABAG held a workshop to begin the process of developing strategies to cope with earthquake-related disruptions to airports. Some of the conclusions from the workshop and studies are:

• More work needs to be done on liquefaction and its potential impact on runways, including connections between existing and newly constructed runways.
• Improvement is needed in emergency planning at airports; emergency coordination among airports and between airports and the rest of the transportation system needs to be improved.
• Alternatives need to be identified for handling large commercial and cargo jets if quakes impair the capacity of Bay Area commercial airports. Options include nearby commercial airports such as Sacramento, as well as larger general aviation airports both within and outside the region.

Airports are a key to getting good emergency response directly following an earthquake, and they are also an important part of the region's economy, making them doubly important in quake recovery. The Metropolitan Transportation Commission's Trans Response Plan integrates response and recovery efforts among all modes of transportation. The plan coordinates the activities of transportation agencies at all levels of government, and includes transit and airports. ABAG also continues to work on some of the issues raised at the workshop, such as liquefaction. While future Bay Area quakes will probably be more destructive than the one in Seattle, it is clear that airport emergency planning can make a real difference in the aftermath.

Jeanne Perkins, ABAG, 510-464-7934, JeanneP@abag.ca.gov