A. Because Japan is a net-exporter of capital. Money that would otherwise be slated for overseas investment in search of higher yields is suddenly diverted to domestic use. In Addition, Japanese insurers invest large amounts overseas in higher-yielding instruments and are forced to bring those funds home to pay claims. Foreign insurers also have to buy JPY to pay claims.
The all-time low in USD/JPY came after the Kobe earthquake in 1995 on just such a reaction.
