Tuesday, December 8, 2009

open hazards

open hazards
What is the prediction (in contrast to the prediction)?

While the dictionary defines forecasting as a synonym for prediction, we consider a prediction as to indicate the likelihood or probability of the earthquake at a particular site during a certain time window, within a certain size range. In contrast, we find a prediction that the specification issued earthquake, or not act in a certain place during a certain time window, within a certain size range. A prediction of the probability statement, although a binary prediction explanation. No prediction can be validated by observing a single one, but one prediction method can be validated by a large number of observations. Conversely, the individual predictions are validated by one password.

What prediction is probabilistic?

Probabilistic forecasting is a compilation of spatial probability density function of lead time with probability conditional probability. That is the probability that the earthquake will occur within a certain amount, conditioned on the observation that no earthquake occurred in recent years. Probability sample of statement would be expected to "have 40% chance that the earthquake with size between 6.5 and 7.0 occur within a radius of 20 km around the X site during the next 3 months."

Earthquake forecasts are currently being made?

Yes. The official estimate for the State of California for collaboration between the S. U. Geological Survey, the California Geological Survey, and a large group of scientists from universities and commercial companies. The estimates used to determine rates of earthquake insurance in California.

What are the methods currently used to predict earthquakes?

United States Geological Survey, which has three Working Groups on Probabilities California Earthquake, develop a long-term forecasts for the region earthquake in California since 1988. The forecasts are based on data describing the historical average major earthquakes and geological data obtained from paleoseismic studies of active fault trenching on track, and instrumental data. The results of the study 30-year probabilities for large earthquakes, with magnitudes typically M> 6.7, the major earthquake fault in California. The process by which the probabilities calculated on extensive consultation and cooperation between more than 100 scientists from a number of years. Expert opinion has an important role. Analysis of the predictions were published recently in the scientific journal Nature ( "Earthquake Shaking Up Theory, Nature, volume 46, pp. 870-872, October 15, 2009).

Other forecasts were developed at the time of accelerated Release (AMR) method, developed by scientists in the United States and Europe, the epidemic Type Aftershock Sequence (ETAS) method scientists in Japan, the United States and in Europe, and back on the M8 SEEKING developed back precursors (RTP) method scientists in Russia, the PSI-method developed by scientists in New Zealand, the USGS step method for calculating 24-hour probability of ground shaking caused by the aftershocks of large earthquakes, and methods different based on the soil and measures dífhoirmiúchán pressure on the land.

OH forecasting methods based on ideas of the peer review of the literature for the past decade or more. The data driven methods, using the ANSS catalog of earthquakes from online sources, also known as observational laws including the Gutenberg-Richter relation and the Omori-Utsu law aftershock frequency. When the parameters of the laws to fit the observations from the past, the calculation of future probabilities. An example of this type of method of the USGS-step method used to calculate probabilities aftershock 24 hours. The advantage of the FP method can be applied in a uniform manner throughout the world, and requires no knowledge of the local geology. Methods similar to those examined repeatedly in recent years, and still test a variety of statistical techniques. The resulting predictions can be different from the official forecasts developed by the S. U. Geological Survey, used the method described above.

How probability forecasts are usually validated in scientific and financial community?

Forecasts are validated through a process called a process called back-testing and monitoring. In back testing, historical data is divided into stages (for details), and for a period of testing (posterior data). Projections made using data prior to events occurring during the interval rear projection. The accuracy of the projections to score then various statistical tests. Predicts achieve a preset level of accuracy are considered to be validated on the confidence level of detection. By monitoring the actual real-time predictions calculated from the highly respected events. The results scored with the same types of statistical analysis. Many researchers consider that a higher level of validation is to test back, because the answer "not" know in advance. But it can take many years to monitor the accuracy of forecasting method to determine when a test result back to respond normally within days, few weeks or few months at most.

How to validate OH, the estimates?

Open dangers to validate, to projections with the same types of statistical tests used in the weather / climate / forecast financial community. The tests used to determine solution, is the ability to estimate among other results, reliability, or the predicted frequency of events is consistent with the observed frequency of events, and sharpness, regardless of whether the events are inclined to happens at the high forecast probabilities, and no bias low forecast probabilities of events, compared with methods where the events tend to average values in the vicinity of the probability.

OH Why choose this approach to validate the estimates?

Open the dangers of the opinion that it is best to test procedures to be standardized through extensive use in other areas, other than inventing new tests statistics using the property and use them not well understood.

OH as far as possible to predict earthquakes? What is available currently?

Method calculates the risk of a full Open likelihood of earthquakes in space and time, and usually more than magnitudes M> 5.0. Furthermore, the methods that applied specifically to calculate probabilities for various magnitudes to achieve. Opening such methods applied to risk the chances for large earthquakes with the amount of M> 8.0 in regions such as Indonesia calculation when they occur.
 
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