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NPS Geologic Hazards Management


Geologic Monitoring
Mount Redoubt, Lake Clark National Park and Preserve, AK.

Overview of NPS Policy

Attempts to prevent or control naturally occuring geologic processes are generally expensive, often futile, and typically have harmful impacts that can outweigh their benefits. The NPS tries to save lives and money by acquiring scientific information about the nature of a park's geologic hazards and the degree of risk they represent, then incorporating that information into the planning process and other park management decisions so that exposure of people and facilities to hazards is minimized.

Through geologic mapping and analysis of deposits and landforms, geologists can reconstruct the history of an area for many millions of years, and find evidence of the geologic forces that created today's landscape. The locations where hazardous geologic processes occurred in the past are often the places that are most likely to be affected by geologic hazards in the future. Some obvious examples include fault scarps, zones of rock rubble (talus) at the bases of cliffs, volcanic deposits, and avalanche chutes. Less obvious geologic processes also have the potential to affect the human environment. Examples include hidden fault zones, swelling clays and soils, and areas subject to infrequent though catastrophic slope failure, subsidence, or flooding.

The timing of past hazardous activity must also be carefully considered. An event that has recurred frequently in the past few thousand years may be more likely to occur again in our lifetimes, whereas activity that last happened millions of years ago in a given location is generally less likely to occur there again. For most types of hazards, large destructive events are less frequent than smaller, less damaging activity. Small events may serve to release geologic stress, for example, by allowing a fault to slip in small increments or a volcano to eject molten rock rising from deep in the earth in a series of minor eruptions. Long periods of quiescence at places that have a history of activity in the recent geologic past may be ominous rather than reassuring, indicating buildup of geologic stress that must eventually be released in a catastrophic event.

Since the magnitude or danger of a potential geologic hazard is not always obvious to the untrained eye, it is important that geoscientists be involved in the early phases of land management planning and project planning. The role of the scientist is to provide the best available information to enable park management to make informed decisions. Integrating geologic hazards information into the NPS planning process reduces the long-term cost of park projects, eliminate the time and cost of repairing unanticipated damage, and possibly save lives.

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Last Updated: March 17, 2011