Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

On the Seismicity of the Middle East 331Table 7. Recurrence-Rate Relations for the Middle East and forSelected Areas in the Middle EastParameters Relation Standard No. of Remarksdeviation events usedlog N = -0.979 I0 + 8.44 0.12 4962 Middle Eastlog N = -1.306 ML 7.73 0.14 5006 Middle Eastlog N = -1.404 ML + 7.64 0.19 1297 Turkeylog N = -0.800 I0 + 6.59 0.17 1299 Turkeylog N = -0.981 ML 5.14 0.19 472717log N = -1.104 ML 5.92 0.12 534 718log N = -0.650 ML 2.71 0.2464 720log N = -1.770 ML 8.94 0.31 474353log N = -1.166 ML 5.84 0.08 314 348log N = -1.419 ML + 6.58 0.23 105347I I I I I I2.52.0o no. of events used 5006+ no. of events used 9461.5lx1 .00.5lYWn 0.00Z5 -0.530" -1.0s-1.5log N = -1.306 ML + 7.73-2.0I I I I I I3 4 5 6 7 aLOCAL MAG. ( ML )Figure 5. log N vs. ML relation for the Middle East.The value of b given by equation (7) is found in the high value range, whichis related to young orogenic belts. Values of b ranging between 0.65 to 1.8 areobtained for different parts of the Middle East that have different geological agesand seismotectonic characteristics. For southern Iran, b is equal to 1.8.The mean return period of earthquakes of a given magnitude or intensity couldbe calculated using the given equations. For the Middle East the following relationmay be used for calculating the return period of an earthquake of magnitude equalto or larger than ML: