 |
||
 |
Earthquake Predictions Fiji-Tonga Region |
|
© Peter Adams, iStockphotos Inc. All rights reserved.
THE FIJI-TONGA REGION is newly defined as of February 2009 to include areas which fall within ≈500 km radius*
of a center point at Lat -20.67° and Lon -178.40° between Fiji
and Tonga. This region includesTonga, but excludes
Samoa.
Since 1975, the region has experienced 210 strong (M6.0-6.9),
17 major (M7.0-7.9) and one great earthquake (M8.0).
(USGS/NEIC & Google Earth sources)
*The radius is 500 km plus an ≈10% error margin of about 50 km in order to
include earthquake events that may occur close to the regional boundary.
All earthquake predictions for the Fiji -Tonga 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 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.
_____________________________
SCROLL DOWN FOR TABLES
_____________________________
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, 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.
FIJI-TONGA REGION
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. 13
PREDICTED M6.3 Expected Date/Location Original prediction 22nd Aug Aug 25+/-3 days (UTC) 2009 Predicted at 0736 hrs UTC (time window open to 2nd Sept) Probability of event >85% within ≈500 km of Lat -20.67 Lon -178.4
|
|
|
OBSERVED M5.2 Observed Date/Location |
No. 12
PREDICTED M4.8 Expected Date/Location Original prediction 11 January 14 January +/-3 days (UTC) 2009 Predicted at 0514 hrs UTC (time window open to 21 January) Probability of event >85% within 500 km of Suva
|
REVISION nil |
| OBSERVED M4.7 Observed Date/Location Magnitude accuracy 97.9% 19th January at Lat 34.67 Lon 141.59 Predicted 8 days ahead 525 km SE from Suva (USGS source) Fiji Region |
Earlier tables have been removed to save space