UPDATE 1-Major China airlines' Aug passenger volume drops

(Adds China Eastern data, attributes figures to airlines)

SHANGHAI, Sept 16 (Reuters) - Passenger traffic at China's three major airlines, including flag carrier Air China (601111.SS) (0753.HK), fell sharply in August from a year earlier as strict security measures for the Beijing Olympics deterred travel, the carriers said on Tuesday.

The airlines began posting year-on-year traffic declines in May, hit by a devastating earthquake in southwest China and security steps ahead of the Games, which reversed a steady record of growth fuelled by China's booming economy.

Although many industry executives have said air traffic was likely to recover after the Games, Air China also cited a weaker tone in the overall economy as a factor weighing on its weak August data.

Air China said its passenger volume in August sank 16.6 percent in August from a year earlier to 2.77 million, while China Southern Airlines (600029.SS) (1055.HK) posted a 16.2 percent drop to 4.88 million.

Shanghai-based China Eastern Airlines (600115.SS) (0670.HK) said its passenger volume slumped 23.06 percent to 2.92 million.

Analysts said visa restrictions and other security measures in the months leading up to the Games were the main factor behind a drop in the carriers' international traffic.

Domestic travel on China's three major carriers had also been affected by a severe earthquake in Sichuan province in May, which led to the cancellation of conferences and other events. (Reporting by Fang Yan; Editing by Edmund Klamann)