Seismic activity over the past few months forced Gold Fields Ltd. to cut its production forecast for its fiscal second quarter Thursday.

The South African gold mine operator said it now expects to produce 900,000 ounces for the quarter ended in December, down 2.8 percent from a previous estimate of 925,000 ounces.

The company blamed seismic disturbances, including one at its Driefontein mine that caused production to shut down for 7 days in December while it conducted a search and rescue operation.

Shares fell 23 cents to $13.64 in afternoon trading.