5.2.1 Natural Disaster Risks in Jinan
Jinan is one of the cities which regularly suffers from natural disasters.Various disasters and risks can threaten the safety of the historic personalities’ residences to varying degrees, endangering the structures.Meanwhile, physical and chemical erosion undermine the building materials persistently.
In history, there have been four devastating earthquakes above 5 magnitude in the jurisdiction of Jinan.the city has been affected by More than 30 times external earthquakes.The most influential one was the 8.5-magnitude earthquake that occurred in the Yuncheng area in 1668.In recent years, there have been 14 earthquakes above 2 magnitude.Among them, a magnitude 3.5 earthquake occurred in Jiyang district during January 2011.In view of the complicated geological structure conditions and the status of provincial capital of Jinan, in 2006 the State Council listed Jinan city as one of the 11 key earthquake surveillance and defense cities for the next 15 years.In 2011, the Earthquake Preparedness and Disaster Reduction Regulations in Jinan were implemented.However, according to the Seismological Bureau, there are 11 geological fault zones in Jinan, but they are all inactive faults since the Quaternary.According to earthquake monitoring, Jinan will have no major earthquake above 5-magnitude in recent years.[13](https://www.daowen.com)
Meanwhile, rainstorms, floods, droughts and hails occur from time to time.On 10th July 1991, 18 towns around Jinan City were hit by hail and tornadoes.In mid-July 1934, the temperature in Jinan reached 43.3 °C, and many people died of heat stroke[14].
Jinan city is surrounded by mountains on three sides.The terrain is high in the South and low in the North.The city center is in a low-lying area which is prone to floods.Additionally, the city drainage facilities are outdated, and floods can easily trigger waterlogging throughout the entire urban area.There has been several serious urban waterlogging in the history of Jinan.In 1921, from July, more than 40 days of heavy rain washed down the railway lines.The Yellow River overflowed, collapsed houses, and flooded fields full of immature crops.Beginning in June 1926, a drought occurred in Jinan, followed by heavy rain in early August, which severely devastated the lower areas in Jinan, and caused numerous houses to collapse.At the end of July 1930, violent wind and rain in Jinan destroyed thousands of houses.In the beginning of July 1935, a flood caused the houses along the river in Nandazhai to disappear.More than 1,000 houses collapsed and 22 people died.On 15th July 1942, a rainfall of 146.9 mm in 3.5 hours in the urban area killed 39 people, more than 8,200 houses collapsed, and 1600 hectares of crops were affected.From July to August 1953, rainfall caused more than 8,000 houses to collapse.On 13th July 1962, the Jinan area was hit by a torrential rainstorm.The average rainfall in the urban and suburban areas reached 298.4 mm within 6 hours.The torrential rain was the largest deluge since Jinan city had a rainfall record in 1916, causing serious damage to more than 11,000 houses, 440,000 square meters of roads and causing 22 bridges to collapse.On 22th July 1963, heavy rain and flood caused the collapse of 1,350 houses and killed 9 people.From 26th to 27th August 1987, torrential rain occurred in Jinan.According to official records, daily rainfall reached 270 mm, and the average urban rainfall reached 315 mm.The rainwater in the urban area and the Southern mountainous area caused the 2.6 meters high above the warning level, which triggering flooding in urban areas that resulted in 47 deaths and more than 11,000 houses to be destroyed.On 18th July 2007, Jinan was hit by a torrential rainstorm.The maximum precipitation in the urban area was 151 mm in one hour.34 people were killed, 6 people missing, and 1,800 houses collapsed, 14,000 square-meters’ of urban roads were damaged.[15]