For the following moment tensor solution

2. We have learned that some moment tensor solutions may exhibit non-double-couple characteristics. Causes of the non-double-couple sources include two nearby earth- quakes occurring nearly simultaneously, heterogeneity near the source, as well as vol- canic processes. Therefore, moment tensor solutions can be used to infer structure near the fault and complex faulting process. For the following moment tensor solution, show that it can decomposed into two double-couple moment tensors.

(a) Whether the moment tensor solutions are pure double couple?

(b) For those non-double-couple moment tensors, can they be decomposed into two double couples? If yes, calculate the ratio of scalar moment between the two double couple moment tensors.