Bermuda-based re/insurer Aspen Insurance Holdings Ltd said today it had no “known exposure” to property damage, business interruption or liability for any nuclear incidents arising from last Friday’s Japanese earthquake.Aspen added that it had started its claims estimation process but it was too early to issue a loss estimate.The company’s shares have fallen eight percent since the close of markets last Thursday, the day before the Japanese disaster occurred.Aspen also announced estimated post-tax losses of $60 million from last month’s New Zealand earthquake and $30 million from the Brisbane floods in January.It added that it believed losses from the Victoria floods and Cyclone Yasi, both in Australia earlier this year, would be “not material”.Aspen added that its estimated losses from last September’s earthquake in New Zealand remained unchanged at $47 million.