spewed some ash and lava Monday and officials warned residents of Hawaii害羞草研究所檚 Big Island to prepare for a possible larger eruption.

The U.S. Geological Survey warned the island害羞草研究所檚 200,000 residents that an eruption of Mauna Loa 害羞草研究所渃an be very dynamic, and the location and advance of lava flows can change rapidly.害羞草研究所�

The eruption began late Sunday night in the volcano on the Big Island following a series of closely spaced, fairly large earthquakes, said Ken Hon, the scientist-in-charge at the Hawaiian Volcanos Observatory. Magma moved to the surface, although lava flows were contained within the summit area and weren害羞草研究所檛 threatening nearby communities.

There害羞草研究所檚 been a surge of development on the Big Island in recent decades 害羞草研究所� its population has more than doubled to 200,000 today from 92,000 in 1980 害羞草研究所� and many newer residents weren害羞草研究所檛 around when Mauna Loa last erupted 38 years ago.

Most of the people on the island live in the city of Kailua-Kona to the west of the volcano, which has about 23,000 people, and Hilo to the east, with about 45,000. Officials were most worried about several subdivisions about 30 miles to the south of the volcano, which are home to about 5,000 people.

A of the eruption from overnight showed lava lighting up one area, moving across it like waves on the ocean.

The eruption migrated from the summit to the northeast rift zone, a notice from the U.S. Geological Survey said. A rift zone is where the mountain is splitting apart and the rock is cracked and relatively weak - making it easier for magma to emerge.

The eruption Monday was feeding several lava flows, which were not threatening any downslope communities. All indications pointed to the eruption staying in the northeast hazard zone, the USGS statement said.

An eruption from the northeast rift zone could send lava toward the county seat of Hilo or other towns in East Hawaii. It could take lava weeks or months to reach populated areas on this side of the mountain.

害羞草研究所淲e don害羞草研究所檛 want to try and second guess the volcano,害羞草研究所� Hon said. 害羞草研究所淲e have to let it actually show us what it害羞草研究所檚 going to do and then we inform people of what is happening ASAP.害羞草研究所�

Hawaii County Civil Defense announced it has opened shelters in Kailua-Kona and Pahala because it has reports of people self-evacuating along the coast.

The average Mauna Loa eruption is not typically prolonged, lasting a couple of weeks, Hon said.

害羞草研究所淭ypically, Mauna Loa eruptions start off with the heaviest volume first,害羞草研究所� Hon said. 害羞草研究所淎fter a few days, it starts to calm down a little bit.害羞草研究所�

The USGS warned residents at risk from Mauna Loa lava flows to review their eruption preparations. because of a recent spike in earthquakes at the summit of the volcano, which last erupted in 1984.

害羞草研究所淎t this time, it害羞草研究所檚 not a time to be alarmed,害羞草研究所� Big Island Mayor Mitch Roth said.

Portions of the Big Island were under an ashfall advisory issued by the National Weather Service in Honolulu, which said up to a quarter-inch (0.6 centimeters) of ash could accumulate in some areas.

Mauna Loa is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island in the Hawaiian archipelago.

Mauna Loa, rising 13,679 feet (4,169 meters) above sea level, is the much larger neighbor of Kilauea, which erupted in a residential neighborhood and destroyed 700 homes in 2018. Some of its slopes are much steeper than Kilauea害羞草研究所檚, so lava can flow much faster when it erupts.

During a 1950 eruption, the mountain害羞草研究所檚 lava traveled 15 miles (24 kilometers) to the ocean in fewer than three hours.

Tourism is Hawaii害羞草研究所檚 economic engine but Roth predicted few problems for those on vacation during the eruption.

害羞草研究所淚t will be spectacular where it is, but the chances of it really interrupting the visitor industry 害羞草研究所� very, very slim,害羞草研究所� he said.

For some, the eruption might cut down on some travel time, even if there is more vog, or volcanic smog caused by higher sulfur dioxide emissions.

害羞草研究所淏ut the good thing is you don害羞草研究所檛 have to drive from Kona over to Hawaii Volcanoes National Park to see an eruption anymore,害羞草研究所� Roth said. 害羞草研究所淵ou can just look out your window at night and you害羞草研究所檒l be able to see Mauna Loa erupting.害羞草研究所�

Julia Neal, owner of Pahala Plantation Cottages, said the eruption brings some relief after many preparedness meetings, and much wondering about what the volcano will do.

害羞草研究所淚t害羞草研究所檚 exciting,害羞草研究所� she said. 害羞草研究所淚t害羞草研究所檚 kind of a relief that it害羞草研究所檚 happening and we害羞草研究所檙e not waiting for it to happen.害羞草研究所�

News that the eruption migrated from the summit to the northeast rift zone and that lava isn害羞草研究所檛 threatening any downslope communities also brings relief, she said.

A few future guests from the U.S. mainland called Neal 害羞草研究所渁sking me to make a prediction, which I can害羞草研究所檛,害羞草研究所� she said. 害羞草研究所淪o I said, just stand by.害羞草研究所�

害羞草研究所擟aleb Jones, The Associated Press