Along with the humanitarian disaster caused by the earthquake and the tsunami, Japan is also beginning to face the economic cost of the catastrophe. The Bank of Japan has announced a multi billion dollar cash injection to stabilise the economy. But that didn't stop shares from tumbling in Tokyo today. The Nikkei ended the session down almost 7-percent. With huge parts of the country's infrastructure damaged, Japanese industry is facing a mountain of problems. And it could be some time before the country returns to business as usual.