Can earthquakes cause land subsidence?
Land subsidence is a gradual settling or sudden sinking of the Earth’s surface. Subsidence can also be caused by natural events such as earthquakes, soil compaction, glacial isostatic adjustment, erosion, sinkhole formation, and adding water to fine soils deposited by wind (a natural process known as loess deposits).
How are earthquakes related to subsidence?
Earthquakes are commonly associated with subsidence. When two blocks of the earth’s crust slide against each other, causing an earthquake, ground movement may occur, raising or lowering the ground surface. Another example of natural subsidence can be found in regions where caves are common.
What is earthquake and subsidence?
Subsidence, or lowering of the ground surface, often occurs during earthquakes. This may be due to downward vertical displacement on one side of a fault, and can sometimes affect a huge area of land. Coastal areas can become permanently flooded as a result.
What is the most common cause of land subsidence?
Compaction of soils in some aquifer systems can accompany excessive groundwater pumping and it is by far the single largest cause of subsidence. Excessive pumping of such aquifer systems has resulted in permanent subsidence and related ground failures.
How do you fix land subsidence?
Methods to control or arrest subsidence include reduction of pumping draft, artificial recharge of aquifers from the land surface, and repressuring of aquifers through wells, or any combination of these methods.
What is subsidence surveying?
If you are worried that your property may be suffering from subsidence, a survey will be able to tell you whether that is the case. It is carried out by a chartered surveyor, who will identify if subsidence is present and what the most probable cause is.
What is coastal subsidence?
Coastal subsidence, which can be described as the downward displacement of the land relative to sea level, often occurs in deltaic regions associated with riverine and estuarine sedimentation. On a global scale, eustatic sea levels have risen approximately 125 m since the last glacial maximum 18,000 yr BP.
Where is land subsidence the greatest?
California
Some of the most drastic and best-known subsidence resulting from overuse of aquifers occurs in the San Joaquin and Sacramento Valleys of California, where the land level has subsided up to 10 meters in the last 90 years.
Can poor drainage cause subsidence?
Subsidence is also caused by leaking drains and gutters. Water leaking into the soil under your property washes away the soil foundations from underneath your home, particularly sandy and gravelly soil. Leaking drains also cause water to saturate the ground, causing foundations to give way and subside.
How can we stop ground subsidence?
The subsidence can be prevented by an adequate support system by adopting rib and sill pillars, steel and wood, cable and rock bolting, plugging of cracks, and backfilling by sand, cement mixed tailing, and waste rock.
