GEOLOGY

Detailed explanation-1: -The VAN method is a popular one among the different theories of electromagnetic precursors. This measure changes in the geoelectric potential, called Seismic Electric Signals to predict earthquakes.

Detailed explanation-2: -Hypotheses can be tested in three ways: (i) by comparing the number of actual earth-quakes to the number predicted, (ii) by comparing the likelihood score of actual earthquakes to the predicted distribution, and (iii) by comparing the likelihood ratio to that of a null hypothesis.

Detailed explanation-3: -Scientists estimate earthquake probabilities in two ways: by studying the history of large earthquakes in a specific area and the rate at which strain accumulates in the rock. Scientists study the past frequency of large earthquakes in order to determine the future likelihood of similar large shocks.

Detailed explanation-4: -Seismic gaps-A seismic gap is a zone along a tectonically active area where no earthquakes have occurred recently, but it is known that elastic strain is building in the rocks. If a seismic gap can be identified, then it might be an area expected to have a large earthquake in the near future.