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Earthquake Predictions
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Torres del Paine National Park, Chile © 2006 David Mathies, iStock Photos, Inc.All rights reserved
THE CHILE REGION. As of 3 April '08, earthquake prediction will be restricted to a circular area of ≈300 km radius* centered on Antofagasta (latitude -23.65°, longitude -70.4°).
Previously, from 19 February to 3 April, the radius was 500 km,
but this smaller circular area of 300 km radius will now make the
earthquake predictions more relavant to the city of Antofagasta.
*The radius is 300 km plus an ≈10% error margin of about 30 km in order to
include earthquake events that occur close to the nominated boundary of the region.
Earthquake prediction for Chile will remain focused on the city of Antofagasta, but occasional predictions will be made for
a similar area around Santiago. The earthquake prediction tables below will clearly spell out which region is invoved.
The above regional focus represents a significant refinement toward improving the accuracy and relevance of earthquake predictions for Chile's most populated region. Previously, from
16 December 2007 to19 Feb 2008, the Chile Region was defined as including areas which fell within a 1500 km radius of Santiago.
All earthquake predictions for the Chile Region are for the largest earthquake in the nominated 10-day 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 for 10 days.
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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SCROLL DOWN FOR TABLES
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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 bi-monthly 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, for each event after 14th July 2008, is given as the predicted magnitude +/-1 magnitude (previously it was given as +/-0.5M). Statistical analyses of over 100 of the latest predictions show that 95% of them 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.
CHILE REGION
See also Long-term Forecasts
No. 12
PREDICTED M5.5 Expected Date/Location Original prediction 23 June 24-28 June (UTC) 2008 Predicted at 2322 hrs UTC (time window open to 2nd July) Probability of event >90% within ≈300 km of Antofagasta
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| OBSERVED M4.3 Observed Date/Location Magnitude accuracy 78.2% 28th June at Lat -21.92° Lon -67.27° 74 km outside range 374 km NE of Antofagasta 180 km ENE Calama, Chile |
No. 11
PREDICTED M5.0 Expected Date/Location Original prediction 20 Apr '08 20-30 Apr (UTC) '08 Predicted at 0252 hrs UTC (time window open to 30 April, plus ≈1 day margin) Probability of event >90% within ≈300 km of Antofagasta
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REVISION nil
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| OBSERVED M4.6 Observed Date/Location Magnitude accuracy 92.0% 1st May, Lat 23.21° Lon -68.60° Predicted 11 days ahead 190 ENE of Antofagasta |
No. 10
PREDICTED M5.8 Expected Date/Location Original prediction 3 Apr '08 3-5 Apr (UTC) '08 Predicted at 1122 hrs UTC (time window open to 13 April, plus ≈1 day margin) Probability of event >85% within ≈300 km of Antofagasta
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REVISED to M4.5 Expected Dates Revised at 0036 hrs on 8 Apr 8-13 April approx. _ |
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OBSERVED M5.1 Observed Date/Location Antofagasta, Chile
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No. 9
PREDICTED M4.9 Expected Date/Location Original prediction 24 Mar '08 24-28 Mar (UTC) '08 Predicted at 0625 hrs UTC (time window open to 3 Apr, plus ≈1 day margin) Probability of event >85% within ≈500 km of Antofagasta
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REVISION nil |
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OBSERVED M6.1 Observed Date/Location Magnitude accuracy 80.3% 24 March, Lat -20.04° Lon -68.79° Predicted 1414 hrs ahead 430 km N of Antofagasta 145 km E of Iquique, Tarapaca |
No. 8
PREDICTED M6.3 Expected Date/Location Original prediction 10 Mar '08 10-11 March (UTC) '08 Predicted at 0748 hrs UTC (window open 10 days to 20 Mar + 1 day margin) Probability of event >75% within 500 km of Antofagasta
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REVISED to M5.3 Expected Dates/Location Revised at 0056 hrs on 12March 12-20 March + 1 day error margin Probability of event >85% within 500 km of Antofagasta Revised range M5.0-M6.0 Antofagasta Region
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OBSERVED M4.5 Observed Date/Location Magnitude accuracy 84.9% 18 March, Lat -24.266° Lon -66.771° Predicted 6 days ahead 380 km W of Antofagasta, Chile Salta, Argentina
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No. 7
PREDICTED M5.4 Expected Date/Location Original prediction 4 Feb '08 4-8 Feb (UTC) '08 Predicted at 0742 hrs UTC (time window open 10 days to 14 Feb) Probability of event >90%
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REVISIONS nil
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OBSERVED M6.4 Observed Date/Location Magnitude accuracy 84.4% 4 Feb at 1701 hrs, Lat -20.14° Lon -70.03° Predicted just over 9 hrs ahead 20 km ENE of Iquique 1470 km North from Santiago, Chile Tarapaca, Northern Chile |
No. 6
PREDICTED M6.7 Expected Date/Location Original prediction 22 Jan '08 22-29 January (UTC) '08 Predicted at 1134 hrs UTC (time window open 10 days to 31 Jan) Probability of event >70% Antofagasta area? |
REVISED to M5.2 Expected Date/Location Revised at 1114 hrs on 26 Jan UTC 26-31 January Revised Range M4.6-M5.8 Chile Region
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OBSERVED M5.0 Observed Date/Location Magnitude accuracy 96.2% 30 January '08 at 1029 hrs Predicted 4 days ahead Lat -42.71, Lon -74.11 Los Lagos, Chile
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No. 5
PREDICTED M5.5 Expected Date/Location Original prediction 10 Jan '08 10-20 January (UTC) '08 Predicted at 0043 hrs UTC (time window open 10 days to 20 Jan) Probability of event >90% Central Chile Region? |
REVIEWS nil
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OBSERVED M4.9 Observed Date/Location Magnitude accuracy 89% 15 January Lat -23.25, Lon -69.55 Predicted 5 days ahead Antofagasta, Chile |
No. 4
PREDICTED M6.4 Expected Date/Location Original prediction, 27 Nov '07 27-30 November (UTC) '07 Predicted at 0715 hrs UTC (time window open 10 days to 7 Dec) Probability of event >80%
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REVISED to M6.4 Expected date/Location Revised 0230 hrs on 6 Dec UTC 6-7 December '07 Revised range M6.2-M6.6 Northern 'Chile Region' Antofagasta to Southern Peru Within 1200 km of Antofagasta (as per prior definition) |
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OBSERVED M5.4 Observed date/Location Magnitude accuracy 84.4% 7 December '07 Predicted 10 days ahead, 75 km WNW of Ica, Lat -13.8, Lon -76.46 the largest quake of the period Southern Peru |
No. 3
PREDICTED M6.0 Expected Date/Location Original prediction, 12 Nov '07 12-20 November (UTC) '07 Predicted at 1055 hrs UTC (time window open 10 days to 22 Nov) Probability of event >75%
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REVISIONS NIL
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OBSERVED M7.7 Observed Date/Location Magnitude accuracy 77.9% 14 November '07 Predicted 2 days ahead, revised 1 day ahead. 170 KN NNE of Accepted: magnitude accuracy ANTOFAGASTA, CHILE not significantly less than 80%. Lat -22.19, Lon -69.84 |
No. 2 (Predicted at 2140 hrs on 16 October, 2007, UTC)
See updates in red in table (revision of 2115 hrs on Oct 20)
PREDICTED M6.8 (Original magnitude M7.5) (Original range M6.6-7.6) |
Expected Date/Location (Original dates 17-18 October) Antofagasta to Aisen Region |
OBSERVED M5.1 Magnitude accuracy 75% Predicted 4.4 days in advance - quake came 8hrs 35 min later than expected. |
Observed Date/Location 25 Oct '07, 8 hrs 35 min 'LATE' Tarapaca, Chile Lat -20.59, Lon -68.73 |
No. 1 (Predicted at 0325 hrs on 16 October, 2007, UTC)
| PREDICTED M4.7 Probability of event >75% Range M4.2 - M4.8 |
Expected Date/Location Nr Coast of Aisen, Chile |
OBSERVED M5.2 Magnitude accuracy 90.4% Predicted 10 hrs in advance |
Observed Date/Location 16 October at 1338 hrs Off Coast of Aisen, Chile Lat -45.94, Lon -76.35 |
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Walking between the geysers of El Tatio