On the reported magnetic precursor of the 1989 Loma Prieta earthquake

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

12

Scientific paper

Among the most frequently cited reports in the science of earthquake prediction is that by Fraser-Smith et al. (1990) and Bernardi et al. (1991). They found anomalous enhancement of magnetic-field noise levels prior to the 18 October 1989 Loma Prieta earthquake in the ultra-low-frequency range (0.0110-10.001 Hz) from a ground-based sensor at Corralitos, CA, just 7 km from the earthquake epicenter. In this analysis, we re-examine all of the available Corralitos data (21 months from January 1989 to October 1990) and the logbook kept during this extended operational period. We also examine 1.0-Hz (1-s) data collected from Japan, 0.0167-Hz (1-min) data collected from the Fresno, CA magnetic observatory, and the global Kp magnetic-activity index. The Japanese data are of particular importance since their acquisition rate is sufficient to allow direct comparison with the lower-frequency bands of the Corralitos data. We identify numerous problems in the Corralitos data, evident from both straightforward examination of the Corralitos data on their own and by comparison with the Japanese and Fresno data sets. The most notable problems are changes in the baseline noise levels occurring during both the reported precursory period and at other times long before and after the earthquake. We conclude that the reported anomalous magnetic noise identified by Fraser-Smith et al. and Bernardi et al. is not related to the Loma Prieta earthquake but is an artifact of sensor-system malfunction.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

On the reported magnetic precursor of the 1989 Loma Prieta earthquake 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 On the reported magnetic precursor of the 1989 Loma Prieta earthquake, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the reported magnetic precursor of the 1989 Loma Prieta earthquake will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1865105

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.