Relationships between Peak Ground Acceleration, Peak Ground Velocity, and Modified Mercalli Intensity in California
Abstract
We have developed regression relationships between Modified Mercalli Intensity (I_mm) and peak ground acceleration (PGA) and velocity (PGV) by comparing horizontal peak ground motions to observed intensities for eight significant California earthquakes. For the limited range of Modified Mercalli intensities (I_mm), we find that for peak acceleration with V ≤ I_mm ≤ VIII, I_mm = 3.66 log(PGA) − 1.66, and for peak velocity with V ≤ I_mm ≤ IX, I_mm = 3.47 log(PGV) + 2.35. From comparison with observed intensity maps, we find that a combined regression based on peak velocity for intensity > VII and on peak acceleration for intensity < VII is most suitable for reproducing observed I_mm patterns, consistent with high intensities being related to damage (proportional to ground velocity) and with lower intensities determined by felt accounts (most sensitive to higher‐frequency ground acceleration). These new I_mm relationships are significantly different from the Trifunac and Brady (1975) correlations, which have been used extensively in loss estimation.
Additional Information
© 1999 Earthquake Spectra. Conversations with J. Boatwright, L. Dengler, J. Dewey, K. Campbell, R. Nigbor, and M. Petersen were very helpful. Jim Dewey provided the intensity data in digital form. Reviews by K. Campbell, M. Trifunac, R. Graves, and N. Field greatly improved this manuscript, as did recommendations of Editorial Board Member P. Somerville.Additional details
- Eprint ID
- 28744
- DOI
- 10.1193/1.1586058
- Resolver ID
- CaltechAUTHORS:20120111-121312741
- Created
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2012-01-12Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences