The recent earthquake and tsunami in Indonesia has claimed the lives of at least 1,350 people. Many more people are missing and the disaster has destroyed homes and businesses across the city of Palu and surrounding area on the island of Sulawesi. Yet after the much larger tsunami that devastated countries around the Indian Ocean in 2004, Indonesia began installing a new early warning system to try to prevent such widespread destruction from happening again. So why is the country once again facing such a severe loss of life? The location of the tsunami may have made the destruction particularly acute, but the country’s early warning system also appears not to have lived up to expectations. A tsunami (Japanese for “harbour wave”) is formed when a disturbance on the sea floor leads to a series of large waves which spread out across the ocean. This disturbance can be caused by a large earthquake, an underwater landslide, or even a volcanic eruption. When the tsunami waves reach shallow water as they move towards the shore, the speed of the wave slows down and causes the water to dramatically pile up. The increase in wave height leads to devastating coastal flooding especially in highly populated, low-lying areas. The height of the wave depends on the size of the tsunami wave but also by the shape of the coastline. For example, tsunamis will have a greater impact where the wave moves through a narrow, elongated bay, like Palu, as it approaches the shore. The earthquake in Sulawesi likely disturbed sediments on the seabed and triggered a local underwater landslide. These two factors combined could explain the six-metre waves that reached Palu. More than one wave can occur during a tsunami, meaning that such events can continue to impact the coastline over a number of hours. It can be the case that the second, third or even later waves can be the biggest. Mast Irham/EPA Early warning systems Unfortunately it isn’t possible to predict exactly when a tsunami may strike a coastal area, but there are clues that can save lives. Indonesia’s main early warning system is made up of a network of tidal gauges that measure sea level, and land-based stations that detect earthquake activity. However, the tidal gauges were so far away from Palu that they only registered a small rise in the water level as the waves started to form. It’s possible the system wasn’t set up to take into account how the waves would grow as they travelled down Palu’s bay. A more advanced warning system is more common in some areas of the world affected by tsunamis and earthquakes, using a series of buoys in the sea to detect any movement of the seafloor. In the event of a tsunami, the buoys send a signal to the local agency responsible for issuing a clear advance warning to coastal residents to allow people to get to higher ground away from the advancing waters. Indonesia has installed a new sea-based system but some researchers have said that it is stuck in the testing phase, and that the ocean buoys deployed aren’t working properly. They point to a potential life-saving early warning system hampered by lack of funding and delays, despite the very real threat from tsunamis in this part of the world following the 2004 event. There may have also been a problem with the way the information about the incoming waves was used. The Indonesian authorities in this case did issue a tsunami warning via text message, but the earthquake destroyed many cellphone towers. Similarly, damage to power lines reportedly prevented sirens from working. The authorities have also been accused of cancelling the warning too soon. Unfortunately, Sulawesi has paid the price for an incomplete tsunami warning system as well underestimating the wave heights that actually struck the coastline.<doc-sep>Instead, the neighborhood was laid waste when the earthquake caused a phenomenon known as liquefaction, undermining and destroying at least 1,747 homes in this part of town alone. Balaroa is now a vast wasteland of debris. Rooftops are all that remain of many houses. The minaret of a mosque, leaning precariously to one side, is one of the few structures still standing. [Surveying the damage: Scenes from the Indonesian tsunami] Across Palu and in neighboring areas, many people are still unaccounted for. Officials put the number of missing at 113, but that was only those who had been reported. An untold number were swept away by the tsunami, especially by the third and final wave that was more than 20 feet high in some places. And many bodies are thought to still be buried under rubble in places like Balaroa. The quake struck at 6:02 p.m. local time, an hour when many would have been at home.<doc-sep>The confirmed death toll from the earthquake and tsunami that struck the Indonesian island of Sulawesi has risen to 832, and the vice-president, Jusuf Kalla, has warned it could reach into the thousands. More than 150 aftershocks followed the 7.5-magnitude earthquake and subsequent tsunami that hit Sulawesi on Friday, causing thousands of homes, hotels, shopping malls and several mosques to collapse. Of the fatalities, 821 were in the city of Palu, with 11 casualties so far recorded in Donggala, the worst-hit area, which is home to 300,000 people. Hundreds of bodies have been found on beaches and authorities fear many may have been washed out to sea. Speaking at a press conference, Sutopo Purwo Nugroho, the spokesman for the BNBP disaster agency, said the area affected was much bigger than originally thought. “The deaths are believed to be still increasing since many bodies were still under the wreckage while many have not able to be reached,” said Sutopo, emphasising that access to Donggala, as well as the towns of Sigi and Boutong, was very limited so the final death toll was impossible to predict. The city of Palu has been completely devastated by the earthquake and tsunami waves, which reached as high as six metres in some areas. In the city, partially covered bodies lay near the shore and survivors sifted through a tangled mess of corrugated steel roofing, timber, rubble and flotsam. One man was seen carrying the muddy corpse of a small child. “Many corpses are scattered on the beach and floating on the surface of the sea,” one local resident, Nining, told local media. The identified bodies are being buried in mass graves, Sutopo said. Sutopo confirmed there was no electricity in Palu and Donggala, while drinking water and fuel were running out. There was limited access to heavy equipment needed to help rescue efforts, so the search for people trapped in the rubble was mostly being carried out by hand. Rescue efforts are continuing for dozens of people still trapped in the collapsed ruins of the eight-storey Roa Roa hotel in Palu, with voices heard screaming from the wreckage. A 25-year-old woman was found alive during the evening in the ruins of the Roa-Roa Hotel, according to the National Search and Rescue Agency, which released photos of the her lying on a stretcher covered in a blanket. There were concerns about the whereabouts of hundreds of people preparing for a beach festival that had been due to start on Friday, a spokesman for the BNBP said. 01:00 Drone captures aftermath of tsunami on Indonesian island - video At least 540 people had been badly injured, the agency said, as hospitals struggled to cope with the influx of casualties, setting up open-air clinics to treat the injured. Dwi Haris, who suffered a broken back and shoulder, rested outside Palu’s army hospital, where patients were being treated outdoors due to the continuing strong aftershocks. Tears filled his eyes as he recounted feeling the violent earthquake shake the fifth-floor hotel room he shared with his wife and daughter. “There was no time to save ourselves. I was squeezed into the ruins of the wall, I think,” said Haris, adding that his family was in town for a wedding. “I heard my wife cry for help, but then silence. I don’t know what happened to her and my child. I hope they are safe.” The Indonesian president, Joko Widodo, who visited the region on Sunday, said earlier the military was being called to the region to help search-and-rescue teams. One of the first casualties of the earthquake, 21-year-old Anthonius Gunawan Agung, is being hailed a hero after he stayed in the air traffic control tower as the earthquake hit, to make sure that a flight to Bali could take off safely. Agung then jumped from the control tower as it was collapsing, but did not survive the fall. Many residents slept in makeshift shelters, terrified that the powerful aftershocks could topple their damaged homes. Villagers view a ship swept ashore by tsunami in Palu, Central Sulawesi, Indonesia. Photograph: Rio Mario/AP Some voiced criticism of the agency that lifted the tsunami warning. The agency said it followed standard operating procedure and made the call to “end” the warning based on data available from the closest tidal sensor, about 125 miles (200km) from Palu. “We have no observation data at Palu. So we had to use the data we had and make a call based on that,” said Rahmat Triyono, the head of the earthquakes and tsunami centre at BMKG. He said the closest tide gauge, which measures changes in the sea level, only recorded an “insignificant” 6cm wave and did not account for the giant waves near Palu. We have heard nothing from Donggala and this is extremely worrying Jan Gelfand, Red Cross The tsunami was triggered by a strong quake that brought down buildings and sent locals fleeing for higher ground as a churning wall of water crashed into Palu. “We all panicked and ran out of the house” when the quake hit, said Anser Bachmid, a 39-year-old Palu resident. “People here need aid – food, drink, clean water.” Dramatic video footage captured from the top floor of a parking ramp in Palu, nearly 50 miles (80km) from the quake’s epicentre, showed waves bring down several buildings and inundate a large mosque. 01:06 Massive wave hits Palu in Indonesia – video About 17,000 people have been evacuated, the BNBP said. “This was a terrifying double disaster,” said Jan Gelfand, a Jakarta-based official at the International Federation of Red Cross and Red Crescent Societies. “We have heard nothing from Donggala and this is extremely worrying. There are more than 300,000 people living there. This is already a tragedy, but it could get much worse.” Friday’s tremor was also felt in the far south of the island in its largest city Makassar and on neighbouring Kalimantan, Indonesia’s portion of Borneo island. The initial quake struck as evening prayers were about to begin in the world’s biggest Muslim-majority country on the holiest day of the week, when mosques are especially busy. Indonesia is one of the most disaster-prone nations on earth. It lies on the Pacific “Ring of Fire”, where tectonic plates collide and many of the world’s volcanic eruptions and earthquakes occur. Earlier this year, a series of powerful quakes hit Lombok, killing more than 550 people on the holiday island and neighbouring Sumbawa. Indonesia has been hit by a string of other deadly quakes including a devastating 9.1-magnitude tremor that struck off the coast of Sumatra in December 2004. That Boxing Day quake triggered a tsunami that killed 220,000 throughout the region, including 168,000 in Indonesia.<doc-sep>
Terrifying video footage shows massive waves crashing into an Indonesian island as a tsunami struck after a 7.5-magnitude earthquake. In the shocking footage, recorded in Palu, Sulawesi, on Friday, enormous waves can be seen surging forward amid terrified screams. Officials had earlier withdrawn a tsunami warning. This morning, the spokesman of Indonesia's disaster mitigation agency BNPB said at least 48 people had been killed and the death toll was expected to rise. "We have not received comprehensive reports yet because communications are cut. Many bodies were found along the shoreline because of the tsunami, but the numbers are still unknown," he said. The water knocks down homes and smashes into trees, leaving a trail of destruction in its path, as residents cry out and try to run to safety. The video comes as officials have confirmed a tsunami of up to two metres hit the city after a powerful earthquake rocked central Sulawesi. Officials say waters have since receded, but families are missing. Search operations are set to begin at first light to determine how bad the damage is, amid reports of whole families being missing in the aftermath of the natural disaster. Have you been affected? Email webnews@trinitymirror.com (Image: Youtube) (Image: Youtube) Follow our live blog for the latest updates on this story The earthquake hit the island on Friday - just hours after a smaller tremor destroyed buildings, killing one person and injuring 10 others. The US Geological Survey said the second quake was centred at a depth of six miles around 35 miles northeast of the town of Donggala. In the tsunami footage, waves can be seen tumbling at a great speed towards the land, as crowds of people shout and run frantically. The person recording the dramatic scene focuses on the fleeing crowds, before turning back to the water, where giant waves are surging forward. The water then crashes into the island before everything suddenly goes dark, with the sounds of panicked people heard in the background. (Image: Youtube) Moments later, the camera refocuses, showing water streaming below through the streets, bringing chunks of debris with it. The Palu Grand Mall and the Baiturrahman Mosque were hit by huge waves close to the shore, the Jakarta Post reports. Critics have questioned why a tsunami warning was lifted before the huge waves struck in Indonesia. The country’s Meteorology, Climatology and Geophysics Agency (BMKG) first issued a warning for western and central Sulawesi at 5.07pm, but revoked it around 30 minutes later. The country's disaster agency confirmed a tsunami had hit Palu and the city of Donggala, sweeping away homes that were in its path. Earlier, a tsunami warning had been issued for people in Central Sulawesi and West Sulawesi provinces following the earthquake. The same area had been hit by a deadly, 6.1-magnitude quake just hours before. Although the warning was lifted within the hour, officials asked people to remain on the alert as a number of moderate aftershocks hit. "We advise people to remain in safe areas, stay away from damaged buildings," Sutopo Purwo Nugroho, spokesman for the National Disaster Mitigation Agency, said in a TV interview earlier. He added that the national agency in Jakarta was having difficulties reaching some authorities in the area. The Geological Survey put the magnitude of the second quake at 7.5, after first saying it was 7.7. According to Nugroho, the quake was felt “very strongly”. “We expect more damage and more victims,” he said. (Image: REX/Shutterstock) Indonesia sits on the Pacific Ring of Fire and is regularly hit by earthquakes. A series of earthquakes in July and August killed nearly 500 people on the holiday island of Lombok, hundreds of kilometres southwest of Sulawesi. And in 2004, a big earthquake off the northern Indonesian island of Sumatra triggered a tsunami across the Indian Ocean, killing 226,000 people in 13 countries, including more than 120,000 in Indonesia. Footage of the incidents today, posted on social media, shows a number of buildings collapsed, with mounds of rubble lying on the ground. Other clips show locals screaming and crying. (Image: REX/Shutterstock) (Image: Youtube) Last month, we reported that the Indonesian island of Bali had been hit by a major tremor for the third time in less than a month. Panicked holidaymakers and locals rushed into the streets amid fears buildings would collapse during that incident.