Amount of ash in plume above Hawaii volcano decreases

Lava shoots into the night sky from active fissures on the lower east rift of the Kilauea volcano, Tuesday, May 15, 2018, near Pahoa, Hawaii. (AP Phot

Lava shoots into the night sky from active fissures on the lower east rift of the Kilauea volcano, Tuesday, May 15, 2018, near Pahoa, Hawaii. (AP Phot

Lava shoots into the night sky from active fissures on the lower east rift of the Kilauea volcano, Tuesday, May 15, 2018, near Pahoa, Hawaii. (AP Phot

Lava shoots into the night sky from active fissures on the lower east rift of the Kilauea volcano, Tuesday, May 15, 2018 near Pahoa, Hawaii. (AP Photo

Lava shoots into the night sky from active fissures on the lower east rift of the Kilauea volcano, Tuesday, May 15, 2018 near Pahoa, Hawaii. (AP Photo

Lava shoots into the night sky from active fissures on the lower east rift of Kilauea volcano, Tuesday, May 15, 2018 near Pahoa, Hawaii. (AP Photo/Cal

Tommie Joy Higgins of Hawaiian Paradise Park, Hawaii, stands on an old lava flow from 2014 as she watches plumes of volcanic gases rise from nearby ac

Tommie Joy Higgins of Hawaiian Paradise Park, Hawaii, stands on an old lava flow from 2014 as she watches plumes of volcanic gases rise from nearby ac

This combination of satellite images provided by DigitalGlobe shows an area by the Kilauea volcano near Pahoa, Hawaii, on May 24, 2017, top, and May 1

This photo from the U.S. Geological Survey shows activity at Halema'uma'u Crater that has increased to include the nearly continuous emission of ash w

PAHO, Hawaii (AP) — A geophysicist says a plume that's rising from the Kilauea volcano summit on Hawaii's Big Island does not contain as much ash as it did on Tuesday.

Mike Poland with the U.S. Geological Survey said Wednesday the plume seems to be made largely of rock dust.

Because there's little wind, the plume for the most part is rising vertically over the summit.

USGS scientists will not monitor the plume from a summit observatory because of fears of falling ash.

Instead, they will operate from a backup command center at the University of Hawaii at Hilo.

Warnings to pilots are still in place because of the plume that reached 12,000 feet (3,658 meters) Tuesday.

The volcano has been spewing lava from fissures that opened up on its flanks for two weeks.