The correlation between b-value and fractal dimension (D) for seismicity
Wang Wei-Chian
Abstract
Seismicity has fractal structures in space, time, and magnitude
distributions, as expressed by the fractal dimension D of the epicenter
distributions, Omori¡¦s exponent p of the aftershocks, and the b value of the
Gutenberg and Richter relation, respectively. There are correlations
among these scaling parameters in different way. Aki¡¦s relation of D=3b/c is
only a speculation and has not been supported by observation data.
However, Turcotte explained and described the relation by b=D/2
(1986b). Then, Hirata (1989) found the negative correlation (D=2.3-0.73b)
between b and D from the analysis of the real earthquake catalogue in the
Tohoku region. The correlation between b and D need to explore, so
Wang (1993) used an one-dimensional mass-spring model with fractal
distribution of breaking strengths for the simulation of seismicity. The
relations from synthetic seismicity show that b-values for events with
intermediate magnitudes are close to 1, while those for larger events are
from 1.68 to 2.52. For small events, the logN values are almost constant.
Reference
Hirata, T., A correlation between the b value and the fractal dimension of
earthquakes, J. Geophys. Res., 94, 7507-7414, 1989.
(Abstract)(Full text)
Wang J. H., A note on the correlation between b-value and fractal dimension
from synthetic seismicity, TAO, vol.4, No.4, 1993.
(Abstract)(Full text)
Turcotte, D.L., A fractal model for crustal deformation, Tectonophysics,
132, 261-269, 1986.
(Abstract)(Full text)
Course: Seminar II (for second-year MSc students)