Statistical parameter selection for RMS Lg amplitudes [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1994.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 31 pages : digital, PDF file
- Additional Creators:
- Pacific Northwest Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- The Lg regional phase as a measure of seismic magnitude has a long history, beginning with Aki (1969). Aki`s theoretical work was refined by Herrmann (1980), and by Nuttli (1986, 1988). Nuttli used as a measure of magnitude, the third largest amplitude (peak-to-peak) in the 3.6 to 3.2 km/sec velocity (time) window. This measurement was corrected for instrument response, geometrical spreading, and anelastic attenuation, as calculated from information measured in the Lg coda, then extrapolated back to a theoretical amplitude at a distance of 10 km. Nuttli`s methodology is summarized by Hagedorn and Nicholson, by Hansen et al. (1990), and by Israelsson (1992a, 1992b). Many later researchers have continued investigations into the Lg phase waves in order to better use the information in this phase for reliable magnitude/yield estimations. Patton (1988) automated the Lg magnitude measurement procedure by computing a RMS magnitude. Ringdal (1983), Ringdal and Hokland (1987), and Ringdal (1991) continued to refine and test the methodology and its stability. The Lg magnitude is a very stable estimator of energy. Hansen et al. (1990) found that RMS Lg amplitudes from events at Shagan River are extremely stable, as measured at NORSAR. Ringdal (1991) stated that because Lg consists of the superposition of many higher-mode surface waves with group velocities near 3.5 km/sec, it represents a more isotropic energy field than that from Pn. He also found that mb(Lg) may be estimated consistently with a noise standard deviation of about 0.03 magnitude units. Carter, et al. (1991) compared the results from four stations and found noise standard deviations of 0.59-0.90.
- Published through SciTech Connect.
Anderson, K.K.; Simpson, D.B.; Hagedorn, D.N.
- Type of Report and Period Covered Note:
- Topical; 05/01/1994 - 05/01/1994
- Funding Information:
View MARC record | catkey: 14380484