The legal term, "Act of God", does not necessarily imply that a God had a direct intervention which specifically caused a "natural" occurrence or disaster.
In the law of contracts, an act of God may be interpreted as an implied defense under the rule of impossibility, i.e., the promise is discharged because of unforeseen, naturally occurring events that were unavoidable and which would result in insurmountable delay, expense or other material breach. In other contracts, such as indemnification, an act of God may be no excuse, and in fact may be the central risk assumed by the promisor, e.g., flood insurance or crop insurance; the only variables being the timing and extent of the damage. In many cases, failure by way of ignoring obvious risks due to "natural phenomena" will not be sufficient to excuse performance of the obligation, even if the events are relatively rare, e.g., the year 2000 problem in computers. Under the Uniform Commercial Code, 2-615, failure to deliver goods sold may be excused by an "act of God" if the absence of such act was a "basic assumption" of the contract, but has made the delivery commercially "impacticable".
In the law of torts, an act of God may be asserted as a type of intervening cause, the lack of which would have avoided the cause or diminished the result of liability (e.g., but for the earthquake, the old, poorly constructed building would be standing). However, foreseeable results of unforeseeable causes may still raise liability. For example, a bolt of lightning strikes a ship carrying volatile compressed gas, resulting in the expected...