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1999 Jiji earthquake

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The 1999 Jiji earthquake, also known as the 921 earthquake, was a massive seismic event in Taiwan. It occurred on September 21, 1999, at 01:47:12 local time. The earthquake struck near the town of Jiji in Nantou County. It measured 7.7 on the moment magnitude scale and 7.3 on the Richter scale. This event is the second-deadliest earthquake in Taiwan's recorded history.

1999 Jiji earthquake
1999 Jiji earthquake

It released an estimated 2.1 × 10^17 joules of energy. This amount of energy is approximately equal to the yield of the Tsar Bomba. The quake had a profound effect on Taiwan's economy and its people.

1999 Chi-Chi earthquake intensity map
1999 Chi-Chi earthquake intensity map

The earthquake was caused by movement along the Chelungpu Fault. This fault stretches through the foothills of the Central Mountains. The fault line runs through both Nantou County and Taichung County. During the event, the surface rupture reached about 100 km in length. The movement was so intense that some sections of land rose by as much as 5 meters. Near Dongshih, the rupture offset the Dajia River channel. This movement actually created a nearly 100-meter high waterfall.

1999 Jiji earthquake
1999 Jiji earthquake

The earthquake was unusual because most of Taiwan's quakes happen off the eastern coast. This specific location caused much more damage to the island.

As the ground shook, several geological processes occurred. One major effect was soil liquefaction in areas like Yuanlin. This happens when soil behaves like a liquid due to intense shaking. This process caused building foundations to settle and water wells to fill with sand. The earthquake also triggered 132 landslides during the main shock and subsequent aftershocks. Some of these landslides caused rockfalls that crushed houses. The Central Weather Bureau recorded 12,911 aftershocks in the month following the main event. One significant aftershock occurred on September 26 and measured 6.8 on the Richter scale. This aftershock caused already weakened buildings to collapse, killing three more people.

The physical damage to the island was extensive and widespread. In total, 2,415 people were killed and 11,305 were severely injured. The destruction of buildings was massive, with 51,711 structures completely destroyed. Another 53,768 buildings suffered severe damage.

集集武昌宮
集集武昌宮

In Taipei City, the 12-story Tunghsing Building collapsed. This collapse was linked to poor construction. Investigators found that structural pillars and beams were stuffed with plastic bottles and newspaper. This was done instead of using proper brick and concrete. In Nantou County, towns like Puli suffered heavily, with 846 deaths reported. Taichung County saw at least 1,074 deaths and 3,648 injuries. The total economic damage was estimated at NT$300 billion, or about US$10 billion.

Infrastructure across Taiwan faced a total breakdown. Power was cut to a large part of the island. This happened because of damage to power stations and transmission stations. Additionally, Taiwan's three nuclear power plants underwent an automatic shutdown. It took two days for the nuclear plants to restart. Taipower reported that 59% of the country had power restored one day later. Transportation was also heavily impacted. 102 major bridges were badly damaged, and many had to be torn down. The Central Cross-Island Highway was also badly damaged. This highway was the only major complete route across the mountains in central Taiwan.

Tonshin Building collapsed after 921 earthquake
Tonshin Building collapsed after 921 earthquake

Rescue efforts involved many different groups working together. The Taiwanese military was mobilized to clear roads and distribute supplies. They also played a leading role in recovering the dead. International help arrived from over 20 countries, including more than 700 rescue workers. Some survivors were found after incredible amounts of time. A six-year-old boy was rescued 88 hours after the quake. Two brothers emerged alive from the Tunghsing Building after nearly 130 hours. They survived by using water from fire hoses and rotten fruit. The earthquake provided a massive amount of scientific data. Because Taiwan had an extensive sensor network, it produced one of the best data sets ever collected. One station recorded a peak ground motion of 300 cm/s, the highest ever measured.

The disaster led to significant political and social changes in Taiwan. Public anger grew regarding shoddy construction and building codes. This dissatisfaction was cited by a sociologist as a factor in the 2000 presidential election. In response to the disaster, the government enacted the Disaster Prevention and Protection Act on June 30, 2000. Now, September 21 is a day of remembrance. Every year at 9:21 AM, a drill message is sent to all mobile phones. This alert is sent through the Public Warning System to ensure people are prepared. The event remains a defining moment in the nation's modern history.

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🖼️ Images & Media (7)
File:1999 Chi-Chi earthquake intensity map.jpg
1999 Chi-Chi earthquake intensity map.jpg
File:1999 Jiji earthquake.svg
1999 Jiji earthquake.svg
File:Map of 1999 Jiji earthquake.svg
Map of 1999 Jiji earthquake.svg
File:Tonshin Building collapsed after 921 earthquake.jpg
Tonshin Building collapsed after 921...
File:集集武昌宮.jpg
集集武昌宮.jpg
File:Guang Fu 921.JPG
Guang Fu 921.JPG
File:九二一震撼.jpg
九二一震撼.jpg
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