Astronomy and Astrophysics – Astronomy
Scientific paper
May 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000geoji.141..357a&link_type=abstract
Geophysical Journal International, Volume 141, Issue 2, pp. 357-373.
Astronomy and Astrophysics
Astronomy
5
Earthquakes, Eastern Mediterranean, Middle East, Surface Wave Magnitudes
Scientific paper
There have been many attempts to improve parametric catalogues for surface wave magnitudes for earthquakes of this century, and many of these attempts have been based on empirical adjustments to homogenize and complete catalogues without recourse to the instrumental data with which these magnitudes have been calculated. Using the Prague formula with station corrections and a substantial volume of amplitude and period readings of surface waves, culled from station bulletins, we calculated uniformly the magnitude of all significant earthquakes, 1519 in all, in the Eastern Mediterranean region and in the Middle East between 1900 and 1998. We also calculated station corrections and their variation with time, and examined the effect of distance adjustment of the Prague formula on Ms estimates. We find that the current procedure of averaging station magnitudes underestimates Ms. This underestimation depends on the variance and on the number of station magnitudes available for the calculation of Ms, which can be as large as 0.3 magnitude units or more. We also find that station corrections have a rather small overall effect on event magnitude, of less than +0.1, except when the number of observing stations is small, in which case the correction may reach +0.3 magnitude units. Event magnitudes derived from station magnitudes with distance adjustment, calculated from the original Prague formula, are on average 0.1 units larger than Ms without distance correction. We find that for shallow events, Gutenberg's estimates are, on average, larger by 0.12 units and show a significant scatter, with a standard deviation three times the mean value. We find similar differences and scatter for surface wave magnitudes estimated by other workers and agencies.
Ambraseys Nicholas N.
Douglas James
No associations
LandOfFree
Reappraisal of surface wave magnitudes in the Eastern Mediterranean region and the Middle East does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Reappraisal of surface wave magnitudes in the Eastern Mediterranean region and the Middle East, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reappraisal of surface wave magnitudes in the Eastern Mediterranean region and the Middle East will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1129304