Estimating the costs of landslide damage in the United States

Abstract

Landslide damages are one of the most costly natural disasters in the United States. A recent estimate of the total annual cost of landslide damage is in excess of $1 billion {Schuster, 1978}. The damages can be significantly reduced, however, through the combined action of technical experts, government, and the public. Before they can be expected to take action, local governments need to have an appreciation of costs of damage in their areas of responsibility and of the reductions in losses that can be achieved. Where studies of cost of landslide damages have been conducted, it is apparent that {1} costs to the public and private sectors of our economy due to landslide damage are much larger than anticipated; {2} taxpayers and public officials generally are unaware of the magnitude of the cost, owing perhaps to the lack of any centralization of data; and {3} incomplete records and unavailability of records result in lower reported costs than actually were incurred. The U.S. Geological Survey has developed a method to estimate the cost of landslide damages in regional and local areas and has applied the method in three urban areas and one rural area. Costs are for different periods and are unadjusted for inflation; therefore, strict comparisons of data from different years should be avoided. Estimates of the average annual cost of landslide damage for the urban areas studied are $5,900,000 in the San Francisco Bay area; $4,000,000 in Allegheny County, Pa.; and $5,170,000 in Hamilton County, Ohio. Adjusting these figures for the population of each area, the annual cost of damages per capita are $1.30 in the nine-county San Francisco Bay region; $2.50 in Allegheny County, Pa.; and $5.80 in Hamilton County, Ohio. On the basis of data from other sources, the estimated annual damages on a per capita basis for the City of Los Angeles, Calif., are about $1.60. If the costs were available for the damages from landslides in Los Angeles in 1977-78 and 1979-80, the annual per capita costs probably would be much larger. The landslide near the rural community of Manti, Utah, caused an expenditure of about $1,800,000 or about $1,000 per person during the period 1974-76. Because a recurrence for such a landslide cannot be established, it is not possible to develop a meaningful estimate of annual per capita damages. Communities are urged to examine their costs of landslide damage and to evaluate the feasibility of several alternative programs that, for a modest investment, could significantly reduce these losses.