Wednesday, August 19, 2020



In the last few years, news of unexpected sinkholes swallowing cars, houses and people have made headlines with disturbingly high frequency. These reports are mainly coming from Florida, the U.S., where almost the entire state is karst terrain (made of limestone), which means it has the potential for sinkholes. Mexico, Belize and parts of Italy and China are also karst area, but the phenomenon of sinkholes suddenly appearing in apparently stable grounds is mostly American. Experts estimate thousands of sinkholes form every year in Florida alone. 

Sinkholes form when water flowing underground has dissolved rock, mostly limestone and sometimes clay, below the surface, leading to the formation of underground voids.When the surface layer can no longer take the weight of whatever that’s above, it collapses into the void forming sinkholes. These sinkholes can be dramatic, because the surface land usually stays intact until there is not enough support. Then, a sudden collapse of the land surface can occur. 

Here are some sinkholes from around the world . . . 

A giant sinkhole caused by the rains of Tropical Storm Agatha is seen in Guatemala City on May 31, 2010. More than 94,000 people were evacuated as the storm buried homes under mud, swept away a highway bridge near Guatemala City and opened up sinkholes in the capital 

An aerial view of the damaged Gran Marical de Ayacucho highway in the state of Miranda outside Caracas December 1, 2010. Thousands of Venezuelans fled their homes after landslides and swollen rivers killed at least 21 people and threatened to cause more damage. 

People look at a tanker after it fell into a caved-in area on a road in Xi'an, Shaanxi province, July 27, 2013. No casualty was reported in the accident, according to local media. 

A construction vehicle lies where it was swallowed by a sinkhole on Saint-Catherine Street in downtown Montreal, August 5, 2013. 

Pamela Knox waits for rescue after a massive sinkhole opened up underneath her car in Toledo, Ohio in this July 3, 2013 handout photo provided by Toledo Fire and Rescue. Toledo firefighters later rescued Knox without major injuries. Fire officials told a local TV station that a water main break caused the large hole. Picture taken July 3, 2013. 

A rescue team works under a caved-in area on a road in Loudi, Hunan province, June 18, 2013. The road surface sank after a truck drove past. A motorcyclist riding behind the truck was injured, according to local reports. 

A stranded car is hoisted from a collapsed road surface in Guangzhou, Guangdong province, September 7, 2008. The road collapsed and trapped the car in a hole, which measured 5 meters (16.4 feet) in depth and 15 meters (49.2 feet) in diameter, local media reported.  

Policemen check a collapsed section of a crossroad in Hefei, Anhui province August 8, 2009. A taxi and a few motorbikes fell into the hole, local media reported. 

Workers repair a cave-in area on a road in Xi'an, Shaanxi province May 27, 2012. The cave-in measured about 6 meters (20 ft.) in depth, 15 meters (49 ft.) in length and 10 meters (33 ft.) in width, is still under investigation. No casualties were reported, according to local media. 

Indian local villagers walk on a bridge damaged by tsunami hit in Nagapattinam town, 350 km (219 miles) south of the southern Indian city of Madras, December 27, 2004. The death toll in a tidal wave triggered by an earthquake that slammed into coasts from India to Indonesia topped 22,000 as rescuers scoured the sea for missing tourists and soldiers raced to recover bodies amid growing fears of disease. 

A sinkhole which damaged an on-ramp to Interstate 15 in San Diego on February 24, 1998. The hole was caused by a drainage pipe which burst due to heavy rains attributed to El Nino weather patterns and is approximately eight hundred feet long, forty feet wide, and seventy feet deep. 

An aerial view shows the debris of a residential building and a destroyed road in the village of Nachterstedt, July 18, 2009. Three residents were missing in the eastern German village of Nachterstedt after their lakeside home and another building suddenly collapsed into the water. A 350-metre stretch of shoreline gave way next to an old open-cast coalmine converted to a lake, about 170 kilometres south-west of Berlin. 

People stand by a recent caved-in area on a paddy field in Fukou county, Hunan province, January 12, 2013. More than 20 pits formed from the sunken ground surface in Fukou county in four months. According to the local media, the government's initial investigation showed years of mining destroyed the local underground water systems and led to the numerous cave-ins 

A home sits near a sinkhole, about 100-feet wide and 50-feet deep, Saturday, May 5, 2012, in Windermere, Fla. The family was forced to evacuate the home. 

A firefighter stands next to a cave-in at a crossroad in Taiyuan, Shanxi province, December 26, 2012. The cave-in measured 6 meters (20 ft.) in depth, 10 meters (32.8 ft). Three coal gas tubes and one water tube were broken during the collapse and firefighters had to dilute the coal gas at the site, reported local media. 

Rescue workers remove a bus with a crane from a Lisbon street hole November 25, 2003. The bus was parked on a Lisbon street when the ground began to open up and gobble it. No casualties were registered. 

Onlookers examine the damage after a section of a road collapsed in Ostrowiec Swietokrzyski, southern Poland December 19, 2012. A hole, measuring 10 metres (33 ft) deep and at least 50 metres (164 ft) wide, appeared on a road in Ostrowiec Swietokrzyski, reported by local media. 

A truck is seen in a hole after part of the structure of a bridge collapsed into a river in Changchun, Jilin province May 29, 2011. Two truck passengers were injured.

A crater, which the Libyan government said was caused by coalition air strikes, is seen at an area in Bab al-Aziziyah compound in Tripoli May 12, 2011. Libyan officials, who showed reporters around the scene of the air strike, at Gaddafi's Bab al-Aziziyah compound, said three people were killed and 25 wounded. 

Local residents look at a sinkhole near Qingquan primary school in Dachegnqiao town of Ningxiang, Hunan province June 15, 2010. The hole, 150 metres (492 feet) wide and 50 metres (164 feet) deep, destroyed 20 houses. 

People look at a collapsed section of Shunwai Road in Nanchang, China's Jiangxi province, April 25, 2007. No one was injured in the accident;

Members of a television crew stand near a hole in the Paseo Nuevo in San Sebastian March 12, 2008. The hole was caused by a storm that sank numerous boats and caused extensive damage in the Biscay area. 

Cars lie in a sinkhole, caused when a road collapsed into an underground cave system, in the southern Italian town of Gallipoli March 30, 2007. There were no injuries in the incident, according to local police. 

Amusing Planet

Some Sydney sinkholes:

A sinkhole which opened in toffy Wentworth Street, Point Piper in 2017, near Prime Minister Malcolm Turnbull's home, showing that sinkholes respect neither the status of the suburb nor the person.

In another example of an unwelcome intrusion into a posh suburb, a truck had to be removed when it drove into a sinkhole on Bay Street, Double Bay, just after 9am on Jul7 28, 2020.  Woollahra Council said the partial road collapse was caused by a nearby water main which burst due to the overnight downpour.

A three-metre wide sinkhole in O’Riordan Street, Alexandria, June 2016

A 2014 sinkhole in Bilgola, a suburb in Sydney’s northern beaches district, caused by a burst water main, also caused a fire truck to tip at a precarious angle. 

On 2nd November 2005 a section of the roof of the Lane Cove Tunnel collapsed.  An unravelling failure ensued travelled through a height of 17m to the surface forming a sinkhole that undermined the front section of apartments. The collapse occurred during the final excavation stages of the intersection of a ventilation tunnel and the exit ramp to the Pacific Highway.


How sinkholes form:

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