Hawaiian Volcano Observatory geophysicists are conducting a routine GPS survey of Haleakala as part of the U.S. Geological Survey's volcano monitoring.

Haleakala last erupted in the late 1700s and is still considered active. The global-positioning system surveys are completed every few years to look for ground movements that might indicate a change in the activity of the volcano.

A network of 12 stations is being surveyed this week, supplementing the single continuously recording GPS station near the Haleakala summit. Repeated measurements over the past decade have shown no significant movement.

The USGS is being given access to the stations by 'Ulupalakua Ranch, Ka'ono'ulu Ranch, Hana Airport, Maui Pineapple Co., the Department of Hawaiian Home Lands, and Haleakala National Park.