Put volume is picking up in the iShares South Korea Fund (EWY) on reports a South Korean ship has sunk following an explosion along a disputed border with North Korea. EWY is off 35 cents to $48.69 and options volume is 15X the usual, with 97 percent of the volume on the put side of the options chain. The action includes an April 43- 45 put spread at 15 cents, 5000X on AMEX. 11.5K April 45 puts now traded. April puts with strike prices ranging from 43 to 49 are seeing brisk trading. July 44 puts seeing some interest as well.