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Earthquake Predictions
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San Andreas Fault, Southern California
© 2007 William Royer, iStock photos Inc. All rights reserved.
SOUTHERN CALIFORNIA REGION is newly defined
as of 29th May, 2010, to include those areas that fall within a 350 km* radius of Glen Avon, CA, at Latitude 34.012, Longitude -117.484. Since 1975 this region has experienced 11 strong earthquakes (magnitudes 6.0-6.7) and three major earthquakes (M7.3 in 1992 and M7.2 in 1999 & 2010).
(USGS/NEIC source)
* Predicted events must fall within a radius of 350 km of Glen Avon , otherwise they will not be considered successful even if the magnitudes are within the predicted range.
All earthquake predictions for the Southern California Region
are for the largest earthquake in the nominated period, plus
an error margin of about one day, but no attempt is made to make forecasts for all periods because of the constraints of private research. Each table, with its original earthquake prediction, will remain subject to revisions or updates throughout the period.
Why updates may be necessary... because earthquakes interact in a very dynamic system. Just as in reporting the weather, the latest information must be taken into account to improve forecasting.
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STATISTICS FOR EARTHQUAKE PREDICTION For period 13 August 2007 - 12 July 2008 (256 predictions)
SUCCESS RATES*
Mag Observed Events Predicted Events
(How many predicted?) (How many observed?)
Pred. Obs. %Correct Obs. Pred. %Correct
<M4 60 67 = 90% 58 66 = 88%
M4.0-4.9 76 85 = 89% 57 60 = 95%
M5.0-5.9 73 77 = 95% 90 96 = 94%
M6.0+ 25 27 = 93% 29 34 = 85%
___________________________________________ *These statistics are updated periodically and refer to tabled predictions only, as no attempt
is made to predict all large earthquakes worldwide. Note that currently successful predictions are those which are ≈80% accurate on magnitude, and within a 10-day time window (plus an error margin of about one day), reflecting the fact that earthquake prediction is still an imprecise science. However, research here is aimed at improving this margin and currently 75% of all magnitude predictions have an error margin of only 15%. Any apparent numerical discrepancies between the two halves of the above table are due to the error margins: for example, an M6 category predicted quake might have come in at M5.8
OVERALL success rate from 256 predictions worldwide-
Observed events that were predicted (234/256) = 91.4%
Predicted events that were observed (234/256) = 91.4%
SCIENTIFIC: Correlation of Predicted & Observed Magnitudes
There is a highly significant correlation (r=0.90, P< .0001) between the full set of observed and predicted magnitudes, including 'false alarms' (Worldwide N=256 as of 12 July 2008).
EARTHQUAKE PREDICTION TABLES
M= Earthquake magnitude. See HOME page for further explanation of table entries.
Earthquake Location Maps - see the USGS web site for maps of earthquakes in these tables.
New 3-layer Table Format & Prediction Rules (25 Nov 07)
Please read following points to fully explain tables below:
1. The Original Earthquake Prediction, and details relating to it, are given in the top light blue layer of each table.
The 'expected date' (or dates) given here provide the best current estimate of when the largest earthquake event is most likely within the nominated 10-day window (date prediction made +10, or possibly ≈11 days). Please note that the time window now includes an error margin of ≈1 day which may extend it to include some closely predicted events, reflecting the fact that earthquake prediction is an imprecise science. The above estimates and other details may be updated, if necessary, in the next section of the table.
The Expected Range in Magnitude is given as the predicted magnitude +/-1 magnitude, or less (as shown). Analyses show that 85% of predictions can be expected to fall within +/-1M of the predicted values, regardless of the region of the world involved. From 14th July 2008, any predictions which fall outside these limits by as little as 0.1M will be regarded as unsuccessful.
2. Revisions, if required, are given in the mid blue layer of each table, and these revisions are used in the final assessments of the results. Please see the statement above explaining why updates are desirable, and note that revisions are limited to a 10-day window. Revisions usually relate to
earthquake magnitude and expected timing, but may also include location.
3. The Observed Earthquake and details (for the event we were attempting to predict) are given in the bottom dark blue layer of each table. The event recorded here is the largest earthquake for the nominated 10-11 day period. 'PENDING...' simply means that the anticipated event has not yet happened, or that we are waiting for the event to be posted on the web site.
SOUTHERN CALIFORNIA
See also Long-term Forecasts
These Long-term Forecasts now give the approximate timing of the largest regional earthquakes for the lunar period ahead.
The Short-term tables below will be used to make revisable and, generally, more precise earthquake predictions for some of the important events that are indicated as being imminent in the Long-term Forecasts.
No. 26 The zoning has since changed to 160 km from Glen Avon, CA
PREDICTED M3.6 Expected Date/Location Original prediction 7th March 7-10 March (UTC) 2009 Predicted at 0615 hrs UTC (time window open to 10th March) Probability of event >85% within 400 km of San Diego
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| OBSERVED M3.2 Observed Date/Location Magnitude accuracy 88.9% 9th March at Lat 32.33 Lon -115.24 Predicted two days ahead 46 km SSE of Calexico (USGS source) Southern California |
No. 25
PREDICTED M3.6 Expected Date/Location Original prediction 27 Jan 27-31 January (UTC) 2009 Predicted at 0720 hrs UTC (time window open to 5th February) Probability of event >85% within 400 km of San Diego
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| OBSERVED M4.4 Observed Date/Location Magnitude accuracy 81.8% 31st January at Lat 35.42 Lon -117.79 Predicted 4 days ahead 157 NNE of Los Angeles Civic Center (USGS source) ' Southern California' |
No. 24
PREDICTED M3.8 Expected Date/Location Original prediction 11 January 15 January +/-3 days (UTC) 2009 Predicted at 0410 hrs UTC (time window open to 21 January) Probability of event >85% within 400 km of San Diego
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REVISION nil |
| OBSERVED M3.6 Observed Date/Location Magnitude accuracy 94.7% 11th January at Lat 34.30 Lon -116.91 Predicted within hours 45 km N of Banning, Southern CA Southern California |
Earlier tables have been deleted to save space