text: A second spectacular blast from the Calbuco volcano in southern Chile has covered nearby towns and villages in a thick layer of ash. The first eruption in over four decades yesterday sent vast clouds of dust more than six miles into the air, creating an incredible display of lightning and lava against the night's sky. Another unexpected eruption in the Los Lagos Region today heightened fears of local waters becoming contaminated, residents developing severe breathing problems and more flights being grounded. The ash covered cars and houses in cities as far as 18 miles away from the source of the eruption as another massive evacuation effort gets underway. Previous and equally violent eruptions at Calbuco have continued for up to a week, according to a volcanologist from Oxford University who told MailOnline it is impossible to predict what will happen next. The volcano is one of the most dangerous of Chile's 90 active volcanoes but was not under any special observation before it suddenly sprung into life at around 6pm local time yesterday. Emergency officials were taken by surprise and had only a few minutes to issue an alert. Scroll down for video . Ghost town: Most people have abandoned the La Ensenada locality in Puerto Varas (pictured) which has been caked in ash despite being over 18 miles away from the massive eruption at Calbuco volcano . Scared: A 30-year-old from Puerto Varas (pictured) said she saw 'the column of smoke rising up' from the volcano when she looked out of her window' Aftermath: The two violent explosions shot billions of cubic metres of ash into the atmosphere, caking nearby localities like La Ensenada in mounds of abrasive soot . Colossal: Two massive explosions from Calbuco volcano in southern Chile have shot up to ten billion cubic metres of ash over six miles into the atmosphere (pictured) Dangerous: Many people in Puerto Varas (pictured) have become worried about the damage the ash will cause to their health . Stuck: As tractors try to clear the mounds of ash that have blocked the roads, one local said: 'We woke up today with a blanket of fog and it hasn't cleared... We have a layer of smoke above us' Contaminated: Ash from the second blast seriously impared the visibility of drivers fleeing the city of La Ensenada (pictured) near the volcano . Isolated: A masked and hooded woman stands alone among the ash falling in the San Marin de Los Andes area near Calbuco . Evacuation: Thousands have fled their homes after Calbuco erupted unexpectedly on Wednesday and was still pouring ash into the sky on Thursday . Explosion: A second eruption from the Calbuco volcano in Chile (pictured) has forced over 4,000 people to abandoned their homes and covered nearby communities in ash . Dramatic: 4,000 people were evacuated from cities around Calbuco following a second spectacular and frightening eruption today (pictured) Eruption: Residents of Puerto Montt had a clear view of the first terrifying explosion yesterday (pictured) which threw ash and smoke a staggering six miles into the air . Spectacle: The dense ash cloud from Calbuco today created an incredible display of lightning and lava against the night sky . Local authorities have evacuated 4,000 people away from the gas and ash contaminating the air and closed access to the area around the volcano which lies near the cities of Puerto Varas and Puerto Montt - 620 miles south of the capital Santiago. Even Professor David Pyle who has studied over a century of eruptions across Chile's 1000-mile stretch of volcanoes ranks this one  among the strongest - and claims its ash could cross the Pacific to Australia. He ranked this particular explosion 'a three or four' on the Volcanic Explosivity Index which means it could unleash an astonishing ten billion cubic metres of ash into the atmosphere. Professor Pyle told MailOnline: 'Based on a 15km-high plume and an eruption of around an hour and a half, that’s quite strong. This particular volcano has erupted a number of times over the last hundred years. 'Sometimes it has lasted a day and other times it has bubbled on for a few weeks. The activity’s died down for the moment but we don’t know what’s going to happen next.' Many people in Chile are deeply concerned about the harmful effects on their health, adding: 'We woke up today with a blanket of fog and it hasn't cleared. We have a layer of smoke above us.' A 30-year-old from Puerto Varas admitted many people in Chile are deeply concerned about the harmful effects on their health, adding: 'We woke up today with a blanket of fog and it hasn't cleared. We have a layer of smoke above us.' 'People went into a state of panic' as the ash cloud spread, according to Miguel Diaz who lives in Puerto Montt 14 miles away. He added: 'I heard a loud noise as if somebody had detonated an atomic bomb.' Abandoned: Chile's President Michelle Bachelet has declared a state of emergency even though no one is believed to be injured since the first explosion yesterday . Volatile: Bachelet said this eruption at Calbuco is 'more serious and unpredictable' than that of the Villarica volcano which also forced the evacuation of thousands of people . Covered: Resident of the Ensenada locality (pictured) near Calbuco struggled to clear the mountains of ash that had built up on their rooves . Locked out: Local authorities have evacuated 4,000 people away from the gas and ash contaminating the air and closed access to the area around the volcano . Protection: Even residents in the Argentinian city of San Carlos de Bariloche (pictured) donned gas masks to avoid the respiratory damage caused by the ash from Calbuco . Deadly: Smoke and lava spew from the Calbuco volcano, as seen from the shores of Lake Llanquihue in Puerto Varas which is over 18 miles away . 'Even small amounts of ash can be really quite disruptive,' according to Professor Pyle who added: 'It affects power supplies and it can be disruptive to agriculture. You don’t need particularly thick accumulations of ash to start to have physical consequences.' Chile's President Michelle Bachelet has declared a state of emergency even though no one is believed to be injured and the only person who went missing since the first explosion was found on Thursday. She said this eruption at Calbuco is 'more serious and unpredictable' than that of the Villarica volcano which also forced the evacuation of thousands of people. The director of a radio station in Puerto Montt described how hundreds of locals rushed to get gas following the eruption, forcing stations to ration their sales. And supermarkets closed their doors to avoid being looted. LATAM airlines has cancelled flights to and from Puerto Montt because airborne ash can severely damage jet engines. A volcano in the Caulle Cordon of southern Chile erupted violently in 2011, forcing the cancellation of hundreds of flights and the evacuation of more than 3,500 people. Stiff winds blew the ash from that explosion over the border to Argentina where the thick, abrasive soot coated slopes in the sky resort city of San Carlos de Bariloche. And by Thursday afternoon, much ash had made its way to Villa La Angostura, Argentina, a small town about 56 miles (90 kilometers) northeast of the volcano. Cars and streets were coated with a thin layer of ash, but people were otherwise going about their business. 'We are praying that the volcanic activity will be as short as possible,' said mayor Roberto Cacault. The National Mining and Geology Service issued a high alert on Wednesday and set up an exclusion zone of 12 miles around the volcano. Ominous: The first eruption (pictured) sent a huge plume of gas and ash soaring into the atmosphere which was visible from up to 100 miles away . Active: Calbuco (pictured yesterday) is one of Chile's three most dangerous volcanoes and part of an active chain of around 500 that cover the south of the country . Incredible: Smoke and lava shot out of Calbuco yesterday as people watched on from the shores of Lake Llanquihue in Puerto Varas (pictured) Explosion: Residents in nearby Puerto Varas (pictured) went about their business as Calbuco exploded, but local authorities setting up a 12.5-mile exclusion zone around it . Destructive: Volcanoes like Calbuco (pictured) occur at the edges of tectonic plates which make up the earth's crust . Plume: While most people think of volcanoes as spewing lava, many eruptions take the form of super-heated gas and ash (pictured) which is pushed through the earth's crust, covering the sky . Trevor Moffat who lives in Ensenada - some six miles from the volcano - said the eruption yesterday happened without warning. Volcano Calbuco's last major eruption happened in 1961, with a weak eruption following in 1972. He said: 'It sounded like a big tractor trailer passing by the road, rattling and shaking, guttural rumbling ... we left everything there, grabbed my kid, my dog, got in the car with my wife. Mr Moffat, who was originally born in Canada, said he was now driving his family to Puerto Varas. He added: 'All the neighbors were outside, a lot of young people crying. Armageddon type reaction.' Television pictures showed a spectacular mushroom-shaped column billowing into the sky with occasional lighting bolts shooting through it. The eruption was seen up to 100 miles away in neighbouring Argentina. Derek Way, a resident of Puerto Varas, said: 'There are a lot of people out in the streets, many heading to the gas stations to fill up on gas. A friend told me to fill everything we have with water.' Chile, on the Pacific 'Rim of Fire', has the second largest chain of volcanoes in the world after Indonesia, including around 500 that are potentially active. In March, volcano Villarrica, also in southern Chile, erupted in spectacular fashion, sending a plume of ash and lava high into the sky, but quickly subsided. Volcanoes occur at the edges of tectonic plates which make up the earth's crust, either where these plates are moving toward or away from one another. Eruptions occur when magma from the Earth's core forces its way to the surface, exploding through weak points in the crust. Danger: Residents from nearby towns said people were crying in the streets after the volcano erupted without warning at 6pm local time . Shocking: While the first eruption occurred in the middle of the afternoon, the plume of ash and smoke was visible well into the evening from towns 100 miles away in Argentina . Blanket: The last major eruption here was in 1961 when lava flows filled the top crater before spilling down the sides and into a nearby lake . Distant: A view of the ash cloud from the Nahuel Huapi lake, around 100 miles away from the volcano in neighbouring Argentina .
target: A second terrifying eruption from the Calbuco volcano in southern Chile has forced over 4,000 to leave their homes .
  The cities of Puerto Varas and Puerto Montt are covered in ash and locals are becoming frightened for their health .
  Yesterday's blast, which shot ash six miles into the air, was the first since 1972 and the first major one since 1961 .
  No one is thought to have died from the two explosions but Chile's president has declared a state of emergency .