A fissure erupts near the intersection of Kahukai Street and Leilani Avenue in Leilani Estate, Tuesday, May 8, 2018, in Pahoa, Hawaii. Hawaii County officials issued mandatory evacuation orders for two... (Associated Press) 
 
 PAHOA, Hawaii (AP) — The Latest on the eruption of Kilauea volcano in Hawaii (all times local): 
 
 10 a.m. 
 
 Geologists say Hawaii's Kilauea volcano could erupt explosively and send boulders, rocks and ash into the air around its summit caldera in coming weeks. 
 
 The U.S. Geological Survey said Wednesday the risk will rise if the lava drops below the groundwater level beneath the summit's caldera or craterlike basin. That's because an influx of water inside could cause steam-driven explosions. 
 
 The agency says the volcano may eject blocks up to two yards (meters) in diameter a little less than a mile (a kilometer) away. 
 
 It may also send pebbles shooting into the air several miles (kilometers) away. 
 
 There's also potential for ash, steam and sulfur dioxide emissions. 
 
 Kilauea is one of the world's most active volcanoes. 
 
 It has destroyed 36 structures since it began releasing lava into a Big Island residential neighborhood last week. 
 
 ___ 
 
 8 p.m. 
 
 Police have gone door-to-door to evacuate residents near two new vents emitting dangerous volcanic gases in Hawaii. 
 
 The vents emerged on Tuesday near the spots where lava has been pouring into streets and backyards for the past week. 
 
 Authorities initially ordered nearly 2,000 residents to leave two communities in the Big Island's mostly rural district of Puna last Thursday. 
 
 But the new vents prompted Hawaii County to issue a cellphone alert ordering stragglers in the Lanipuna Gardens area to get out immediately. Police followed up with personal visits. 
 
 Fourteen vents have opened since the current lava breakout began. The lava has destroyed 36 structures. ||||| After surviving earthquakes and molten lava, residents of Hawaii’s Big Island now have new threats to worry about: steam-driven explosions, hazardous volcanic smog and acid rain. 
 
 The US Geological Survey’s Hawaiian Volcano Observatory on Wednesday warned of possible explosive eruptions in the coming weeks. That could happen because as lava continues to sink in a lake inside a Kilauea crater, an influx of groundwater could interact with the lava to create steam explosions. 
 
 Those forces would emit “ballistic projectiles” — as small as pebbles or weighing up to several tons. The agencies also said ash clouds would rise to greater elevations, dispensing ash over wider areas. 
 
 “At this time, we cannot say with certainty that explosive activity will occur, how large the explosions could be, or how long such explosive activity could continue,” an advisory said. 
 
 Gov. David Ige asked President Donald Trump to issue a disaster declaration for Hawaii as a result of the ongoing earthquakes and volcano eruption, according to a press release. 
 
 The declaration allows federal funds to begin to flow to state and local efforts in Hawaii. The estimated cost to protect residents over the next 30 days is expected to exceed $2.9 million, according to the governor’s office. 
 
 A brief explosion Wednesday on a Kilauea crater was the result of falling rocks and not the interaction of lava with the water table, the USGS said. 
 
 The Kilauea eruption last week created new volcanic vents on the ground miles east of the summit, releasing slow-moving lava and toxic gas into island communities. 
 
 Officials have warned of dangerous levels of sulfur dioxide gas. 
 
 If winds weaken, that gas and other volcanic pollutants can settle easily with moisture and dust to create a haze called volcanic smog, or “vog,” with tiny sulfuric acid droplets that can pose respiratory problems, according to the US Geological Survey. 
 
 Trade winds could weaken Thursday and Friday, meaning the vog that’s largely been accumulating over the ocean south of the Big Island could pool over a larger portion of it, creating possible health hazards, the National Weather Service says. 
 
 And with high chances of rain on those days, sulfuric acid droplets would fall, creating another menace known as acid rain, CNN meteorologist Michael Guy says. 
 
 Respiratory problems 
 
 At higher concentrations, vog can cause headaches and irritation to the lungs and eyes, the University of Hawaii at Hilo says. 
 
 “Because of their small size, aerosol particles such as those in vog penetrate deep into the human lung and are readily retained,” the USGS says. 
 
 High levels of acidic particles in vog “can induce asthma attacks, especially in adolescents, and can also impede the ability of the upper respiratory tract to remove other potentially harmful particles,” it says. 
 
 For people with asthma and other respiratory problems, “the effects are much more serious, causing a tightening of the airways in the lungs and making it very difficult to breathe,” the university says. 
 
 But it adds: “There’s been no clear evidence that vog causes lingering damage to normally healthy individuals.” 
 
 If trade winds become lighter as predicted later this week, vog could pool northward over parts of the island by Friday, the weather service says. 
 
 But winds are forecast to return — and the vog could be pushed off much of the island — by Friday night, it says. 
 
 Similar to battery acid 
 
 If it rains where vog has collected, acid rain would result. 
 
 “Wherever you have a vog plume, you’re going to have acid rain, if it’s raining,” University of Hawaii meteorologist Steven Businger told CNN affiliate Hawaii News Now. 
 
 What are the effects of acid rain? The droplets of sulfuric acid in vog have the corrosive properties of diluted battery acid, the USGS says. 
 
 “When atmospheric moisture is abundant, these droplets combine with it and fall as acid rain, damaging plants and accelerating the rusting of metal objects such as cars, industrial and farm equipment, and building components,” it says. 
 
 The amount of acid rain depends on the concentration of sulfur dioxide in the air, CNN’s Guy says. 
 
 Determining how acid rain affects human health is complicated, and Guy says the effects on the skin are unclear. 
 
 One direct, immediate threat is not the rain, but rather breathing in the particles in the vog — the very pollutants that caused the acid rain, according to the Environmental Protection Agency. 
 
 “Walking in acid rain, or even swimming in a lake affected by acid rain, is no more dangerous to humans than walking in normal rain or swimming in non-acidic lakes,” the EPA says. 
 
 But acid rain can contaminate household water supplies by leaching metals from building and plumbing materials, the USGS says. 
 
 That includes rooftop rainwater-catchment systems that Hawaii residents use for drinking water. 
 
 “In 1988, the drinking water of nearly 40% of homes using such systems in the Kona Districts of the island was found to be contaminated with lead leached by acid rain,” the USGS says. “Tests confirmed that the blood of some residents of these homes had elevated lead levels.” 
 
 Businger told Hawaii News Now that acid rain is not an immediate health hazard, adding that it’s “the least of their (residents) worries.” 
 
 More vents open 
 
 Other dangers persist, not only in the form of lava but also earthquakes and newly formed cracks. 
 
 Two additional volcanic vents — the 13th and 14th — erupted Tuesday in the Leilani Estates area, where roughly 1,700 residents were asked to evacuate last week. At least 36 structures — including at least 26 homes — have been destroyed. 
 
 On Wednesday, a 15th vent formed — this one in the Lanipuna subdivision, the Hawaii County Civil Defense Agency says. 
 
 Residents were being still allowed to check on their properties from 7 a.m. to 6 p.m. each day but must be prepared to leave at a moment’s notice, the Hawaii County Civil Defense Agency says. ||||| Days, Weeks, Years? Scientists Say Hawaii Volcano Eruption Has No End In Sight 
 
 Enlarge this image toggle caption U.S. Geological Survey via AP U.S. Geological Survey via AP 
 
 Updated at 10:25 p.m. ET 
 
 The eruption at Hawaii's Kilauea volcano continues. The lava has now destroyed at least 35 structures and covered the equivalent of more than 75 football fields. 
 
 Scientists have been tracking this event since it started last week — but there are still big unanswered questions, the biggest of which is when it will end. 
 
 The Kilauea volcano on Hawaii's Big Island has been erupting for more than 30 years. Lava levels in the Pu'u O'o crater and the volcano's summit rose in recent weeks, says Wendy Stovall, a volcanologist with the U.S. Geological Survey. They were "inflating like a balloon, because magma was getting backed up from below," she says. 
 
 Then last week, the magma at Pu'u O'o plummeted. "The whole bottom of the crater floor dropped out and the magma completely drained away from that system," says Stovall. 
 
 Scientists don't know what started this latest event, but there are two possibilities, says Stovall: "Either there's an increase in magma supply, or something blocked the system, something blocked the pathway out of the system." 
 
 In other words, suddenly more molten rock shot up from deep inside the Earth, or there was a clog. Whatever the cause, the pressurized magma had to go somewhere. It turned away from the crater, heading underground, flowing into spaces between the rocks along what's known as the volcano's East Rift Zone. 
 
 That set off a series of earthquakes, including a 6.9 magnitude temblor that hit on Friday and could be felt across the island. Stovall said that by tracking the earthquakes and deformations in the ground, they could see the direction the magma was heading. 
 
 "Honestly it was pretty frightening to see where the magma was going," says Stovall. That's because it was headed toward a lush residential area — Leilani Estates, where more than 1,700 people were ordered to evacuate. Video posted on social media by Demian Barrios shows flaming lava gushing out, destroying a road. 
 
 Here's why the lava rips apart the ground, says Denison University volcanologist Erik Klemetti: "It's like a leaky pipe or a burst pipe, where the magma is moving down the conduit system and it just reaches a point where the pressure builds enough that you start cracking the surface above." 
 
 There are now at least 12 of these fissures in the ground as of Tuesday in and around Leilani Estates, according to Hawaii's civil defense. 
 
 Scientists are tracking earthquakes and the composition of gas coming out of the cracks in the ground, which hints at whether the eruption will intensify. But what will happen longer-term is much more difficult to predict, says Bill Chadwick, a volcanologist at NOAA. 
 
 "We can't really peer through the ground and see it exactly in all its details and intricacies," Chadwick says. Scientists can't predict when this eruption will end. "It could last days, weeks, years. All that's possible. It's hard to say, unfortunately." 
 
 This makes it unique compared with other natural hazards like hurricanes or tornadoes, where there is a clear endpoint, Stovall says. 
 
 "Volcanoes will build up pressure, and then they'll release that pressure in eruption, and then they'll pause," says Stovall. "And then they'll build up pressure again and release the pressure in another eruption and then they'll pause again." 
 
 Stovall adds: "As long as there's magma supplying the system we're expecting more of the same to happen." 
 
 The uncertainty makes it extremely difficult for the residents of Leilani Estates to know what their future holds, which worries Klemetti. 
 
 "When a house today might look like it's perfectly safe, it might get taken out by a lava flow five years from now if the eruption keeps on going," he says. 
 
 At the same time, it provides what Stovall calls a once-in-a-lifetime research opportunity for scientists. "The things that we will learn in the wake of this eruption will change the way we see volcanoes for the future." 
 
 Scientists are trying to gather as much data as possible, and Stovall says that the information they obtain has the potential to change their understanding of how this volcano functions — which could help keep neighboring communities safe in the future. ||||| PAHOA, Hawaii (Reuters) - The Kilauea volcano erupted again on Tuesday, spewing toxic gases out of two new vents and prompting authorities to call for an immediate evacuation of residents from a second neighborhood on the Big Island. 
 
 The County of Hawaii Civil Defense Agency issued an emergency bulletin ordering residents of the Lanipuna Gardens area on the east side of the island to leave their homes. 
 
 “Hawaiian Volcano Observatory confirms 2 new vents. All Lanipuna residents must evacuate now,” the agency said in its bulletin, adding that the two vents had opened near two road intersections and were “actively erupting”. 
 
 Earlier on Tuesday residents of the hardest hit area, known as Leilani Estates, drove through clouds of sulfur and over cracked roads to make desperate and possibly last visits home before another eruption by Kilauea, which has already destroyed 35 homes and other structures. 
 
 David Nail, who recently sold his business and moved to Lelani Estates from Orange County, California after his wife was diagnosed with Parkinsons disease, said a 20-foot wall of lava blocked him from getting close enough to see if his house had been destroyed. 
 
 “All we could do was sit there and cry,” Nail said. 
 
 Earlier in the day U.S. Army veteran Delance Weigel, 71, collected some of his prized possessions as steam and sulfur dioxide gas rose out of cracks in the street. 
 
 “The way it looks now, I thought I’d try one more time to get my things out,” Weigel said. “Whether we lose our home or not, we’ll see. But we’re definitely going to be cut off. You move to paradise, then this happens.” 
 
 FOUNTAINS OF LAVA 
 
 No deaths or major injuries have been reported since Kilauea, which has been in a state of nearly constant eruption since 1983, began a series of major explosions on Thursday, spewing fountains of lava as high as 300 feet (90 meters) into the air and deadly volcanic gas up through cracks in the earth. 
 
 Fissure 12 opened shortly after fissure 11 became inactive, in the forest south of Malama Street in Leilani Estates, in Hawaii, U.S. May 7, 2018. Picture taken on May 7, 2018. USGS/Handout via REUTERS 
 
 (For a graphic explaining the eruption: tmsnrt.rs/2IldVyS) 
 
 Kilauea predominantly pours basaltic lava flows into the ocean, but occasionally experiences more explosive events such as the one that began last week. 
 
 Some 1,700 residents were ordered to leave Leilani Estates, where lava has been bubbling out of some 2-1/2 miles (4 km) of fissures in the ground emanating from Kilauea lava tunnels on the eastern side of the Big Island. 
 
 New areas could be subject to evacuation as fingers of the fissure system slowly spread eastward, threatening neighborhoods that until now had been considered safe. 
 
 “There’s still plenty of magma under the ground. Seismicity is still up,” Hawaii Civil Defense Administrator Talmadge Magno told a community meeting on Monday night. “If things get dicey, you got to get out.” 
 
 On Friday, The southeastern corner of the island was rocked by a powerful magnitude 6.9 earthquake on the volcano’s south flank, the strongest since 1975, and more quakes and eruptions have been forecast, perhaps for months to come. 
 
 Kilauea has opened a total of 14 volcanic vents since it started sending out fountains and rivers of lava as hot as 2,000 degrees Fahrenheit (1,093 degrees Celsius) on Thursday, officials said. 
 
 Hawaii’s 4,028-square-mile (10,430-square-km) Big Island accounts for less than a fifth of the state’s tourism. 
 
 Slideshow (15 Images) 
 
 State data show that in the first three months of 2018, 16 percent of the $4.81 billion visitors spent in Hawaii came from the Big Island, less than half of the levels seen on the islands of Oahu and Maui. ||||| Einat Lev, a volcanologist, is an assistant research professor at the Lamont-Doherty Earth Observatory at Columbia University. Her research, funded by the National Science Foundation, is focused on lava flow dynamics at different volcanoes, including in Hawaii. The opinions expressed in this commentary are solely those of the author. 
 
 (CNN) When asked to draw an erupting volcano, most people draw a steep-sided cone with a big plume of smoke coming off the top. It will likely be a very scary picture, a "run for your life!" situation. This might be why the current eruption of Kilauea volcano, in Hawaii, has surprised many. 
 
 Einat Lev 
 
 This eruption, while typical for Hawaii, doesn't look like that picture. Instead, here we are dealing with an "effusive fissure eruption" on the flank of a shield volcano. This means lava is oozing out of cracks in the ground, on the side of a volcano that is low and wide. 
 
 Running is not necessary -- a typical flow from this eruption moves a few feet per second, so walking is probably fine (but do get away!) 
 
 Lava -- molten rock flowing on the ground for everyone to see -- can be as beautiful as it is dangerous. There is a whole zoo of forms and shapes that lava can take. It can be thick and sticky, building large mounds like the dome that grew in the barren summit of Mount St. Helens between 2004 and 2008, and is still there. 
 
 In extreme cases, lava can be very runny and rush down a mountainside in just a few hours, as happened at Nyiragongo volcano in Africa in 2002. The surfaces of lava flows can be smooth and shiny sheets, or rough, painful to walk on, or rubble, or anything in between. 
 
 Read More
– Authorities have warned of no end in sight to volcanic activity responsible for hundreds of earthquakes and the destruction of dozens of homes on Hawaii's Big Island. Case in point: After a 24-hour lull, two new volcano fissures opened up in the Lanipuna Gardens area Tuesday afternoon—at least one home was destroyed—prompting a warning for the area's 250 residents to "evacuate now," report Hawaii News Now and Reuters. The fissures join 12 other vents, covering 2.5 miles, in the Leilani Estates neighborhood, where 1,700 were evacuated. Though activity has calmed there, Kilauea's ongoing eruption "could last days, weeks, years," a volcanologist tells NPR. "As long as there's magma supplying the system we're expecting more of the same," adds USGS volcanologist Wendy Stovall. At CNN, geologist Einat Lev explains that Kilauea's "effusive fissure eruption" is resulting in lava flows that are slow-moving but threatening nonetheless. "While we cannot tell how long this eruption will last, we can do our best to predict where the lava will go," Lev says. Using constantly updated maps and heat cameras, experts are tracking magma as it flows beneath communities, trying to determine where pressure will force a new fissure to open and how much lava and ash might escape. Other concerns include sulfur dioxide gas, which could turn to acid rain with precipitation expected Thursday or Friday, reports KTLA, and the possibility of explosive eruptions that send boulders flying through the air, which geologists warned about Wednesday, per the AP. Scientists are trying to look on the bright side, though. "The things that we will learn in the wake of this eruption will change the way we see volcanoes for the future," Stovall says.