1. A method for updating an earth model relating to a portion of the earth's sub-surface in a computer readable medium comprising: obtaining an earth model in a computer readable medium, said model including surfaces bounding geological features wherein the geological features are faults or fractures and the model also includes mechanical attributes of the faults or fractures; obtaining time-sequenced microseismic data by receiving acoustic waves caused by microseismic events which are movement of the earth's sub-surface at a plurality of locations below ground; using the microseismic data to identify one or more faults or fractures; processing the microseismic data to determine location and strength related parameters; providing such parameters as an input into the earth model, and updating mechanical attributes of an identified fault or fracture in the earth model.