Revised models for attenuation of Modified Mercalli intensity in New Zealand earthquakes
Abstract
This paper presents simple two-dimensional models for attenuation of Modified Mercalli intensity in New Zealand earthquakes, which improve upon the models published by the present authors in 1999. First, the models now ensure that the attenuation functions in the two orthogonal directions converge to the same value at zero source distance. Secondly, an improved fit has been achieved through a modification of the algebraic form of the log distance term in the attenuation function. An additional improvement is the completion of the attenuation model for Deep events (hc ⩾ 70 km) in the subducting Pacific plate, which was not fully dealt with in our previous paper. Intensity saturation effects are demonstrated. A comparison is made between our New Zealand model and one for the intraplate region of South China where the attenuation rate is considerably lower.