Hydrologic effects of the Pymatuning earthquake of September 25, 1998, in northwestern Pennsylvania
Water-Resources Investigations Report
99-4170
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Abstract
Within hours after the Pymatuning earthquake of September 25, 1998, in northwestern Pennsylvania, local residents reported wells becoming dry, wells beginning to flow, and the formation of new springs. About 120 household-supply wells reportedly went dry within 3 months after the earthquake. About 80 of these wells were on a ridge between Jamestown and Greenville, where water-level declines of as much as 100 feet were documented. Accompanying the decline in water levels beneath the ridge was an increase in water levels in valley wells of as much as 62 feet. One possible explanation of the observed hydrologic effects is that the earthquake increased the vertical hydraulic conductivity of shales beneath the ridge, which allowed ground water to drain from the hilltops. Computer simulations of ground-water flow beneath the ridge between Jamestown and Greenville indicate that increasing the vertical hydraulic conductivity of shale confining beds about 10 to 60 times from their pre-quake values could cause the general pattern of decreased water levels on hilltops and increased levels in valleys.
Suggested Citation
Fleeger, G.M., Goode, D.J., Buckwalter, T.F., and Risser, D.W., 1999, Hydrologic effects of the Pymatuning earthquake of September 25, 1998, in northwestern Pennsylvania: U.S. Geological Survey Water Resources Investigation Report 1999–4170, 8 p., https://pubs.er.usgs.gov/publication/wri994170.
Study Area
Table of Contents
- Hydrologic Effects of the Earthquake
- Summary and Conclusions
- References Cited
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Hydrologic effects of the Pymatuning earthquake of September 25, 1998, in northwestern Pennsylvania |
| Series title | Water-Resources Investigations Report |
| Series number | 99-4170 |
| DOI | 10.3133/wri994170 |
| Year Published | 1999 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | Pennsylvania Water Science Center |
| Description | 8 p. |
| Country | United States |
| State | Pennsylvania |
| Online Only (Y/N) | Y |
| Google Analytic Metrics | Metrics page |