The advancing lava flow from Hawaii's Kilauea volcano has prompted the mayor of Hawaii's Big Island to declare a state of emergency.

Hawaii County Mayor Billy Kenoi issued an emergency proclamation on Thursday in response to the advancing lava flow in the Wao Kele O Puna reaching the edge of rural habitation and following Hawaii's Volcano Observatory raising the lava threat from watch to warning, which means that a hazardous lava flow is imminent, underway or suspected.

"Due to the threat of disaster due to property damage and/or bodily injury to residents of Hawaii Island, and the need for government agencies and representatives from the private sector to mobilize and provide immediate services to our island residents, a state of emergency is authorized," the emergency proclamation reads.

Although the lava flow is slow-moving, scientists at the Hawaiian Volcano Observatory fear that it could reach the Ka'ohe Homesteads subdivision within a week as it is now less than one mile from the edge of the area.

In a statement, the Hawaiian Volcano Observatory (HVO), one of the five volcano observatories within the U.S. Geological Survey (USGS) responsible for tracking volcanoes and earthquakes in Hawaii, said that if the lava advances through ground cracks, which it did several times since Aug. 18, the lava could reach the boundary of the Kaohe Homesteads within five to seven days given its average speed of 250 meters per day since July 10.

"At the average rate of advancement of 250 m/day (820 ft/day) since July 10, we project that lava could reach the Kaohe Homesteads boundary within 5-7 days should lava resume advancing within the crack system," the HVO said in a statement.

Darryl Oliveira, the county's Civil Defense Administrator, said that evacuation has not yet been ordered but the emergency proclamation would give authorities power to restrict access to Ka'ohe Homestead roadways which is crucial for facilitating the safe movement of resident should evacuation becomes necessary.

"We are taking this step to ensure our residents have time to prepare their families, their pets, and their livestock for a safe and orderly evacuation from Ka'ohe in the event the flow continues to advance," Kenoi said.

Oliveira also advised the residents to finalize their evacuation plans and to closely monitor updates from the county Civil Defense, whose employees already go about visiting homes in Ka'ohe to explain to the residents the situation and help them prepare.