环境地质学
Environmental Geology
主讲人,万新南 教授
Prof,Wan xinnan
环境地质学 Environmental Geology
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
6,Pre降水、江河与洪水
7,Mass Wasting Processes 表层整体再塑
（滑坡、泥石流、溶蚀、塌陷）
8、海岸线与海岸塑造过程
9、生态与植被
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
7,Mass Wasting Processes
表层整体再塑
（地面塌陷）
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
The surface of the land is subsiding over
wide areas near Phoenix,AZ,Houston,TX,
Fresno,CA,as well as at other parts of the
world such as Tokyo,Mexico City,London,
and Venice,This subsidence is caused by
the withdrawal of large volumes of ground
water from unconsolidated sediments,
Land subsidence also occurs due to the
solution of soluble rocks; in some cases,
this subsidence may be triggered by man,
Land subsidence may also occur over
mined land.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Land Subsidence Due to Withdrawal of Fluids
Subsidence due to ground-water withdrawal
develops under two contrasting environments and
mechanics,The most extensive occurrence is in
unconsolidated to semiconsolidated sediments
containing confined or semi-confined sand and gravel
aquifers含水层 interbedded with clayey aquitards隔水
层, Another occurrence is in soluble rocks containing
caves or sinkhole deposits; a lowered water table may
cause erosion of cave fill or cave collapse due to loss
of buoyant support from ground water.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
Extensive land subsidence is caused by the withdrawal of
fluids (e.g.,ground water or petroleum) from weakly
consolidated artesian承压 aquifers,The key to
understanding this phenomena is the concept of aquifer
elasticity,Fig9.1 illustrates how the total stress
(lithostatic岩石静压 overburden过载 ) on an aquifer (St) is
supported by stress on the grain-to-grain skeleton of the
aquifer (effective stress = Sk ) as well as the water
pressure in the aquifer (Sw ):
(2.3.1)
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
San Joaquin Valley,CA,California has a greater area
affected by land subsidence than any other state,The
southern part of the Great Valley,California,is intensely
irrigated by ground water,At least 11,000 km2 of this
important agricultural area has subsided more than 0.3 m
since the 1920s creating the world's largest area of intense
land subsidence,According to Poland et al,(1975),an area
113 km long has subsided more than 3 m,with a maximum
of 8.5 m,(Fig9.3) The volume of subsidence amounts to 20
km3 or about half the volume of the Great Salt Lake.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
In 1982 the U.S,Geological Survey studied
movement of growth faults (Fig.9.5) and found that
seven monitored faults in the area of water level
recovery had stopped moving,By contrast,the five
monitored faults in the area where water level has
continued to drop have displacements averaging 1
cm/yr.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Wilmington oil field petroleum
withdrawal at the Wilmington oil
field has caused enormous land
subsidence along the Pacific coast
at Long Beach,CA,The U.S,Navy
shipyards have subsided up to 9m
causing the shipyard to sink below
sea level (Fig.9.10),this required
the $ 100 million construction of
levees大堤 and sea walls to keep
the Pacific from inundating淹没 the
shipyard,Apparently,the
subsidence has been stopped by
injecting salt water into the oil-
bearing formations to restore fluid
pressure.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Wilmington oil field
Small,local subsidence
problems associated with
petroleum extraction has
been known for some time,
In some places,flowing
sand moves up the well
casing,resulting in local
ground subsidence,
Historical faulting at
southern California oil fields
may be related to oil-field
development rather than
deep tectonic forces
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Environmental Geology
主讲人,万新南 教授
Prof,Wan xinnan
环境地质学 Environmental Geology
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
6,Pre降水、江河与洪水
7,Mass Wasting Processes 表层整体再塑
（滑坡、泥石流、溶蚀、塌陷）
8、海岸线与海岸塑造过程
9、生态与植被
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
7,Mass Wasting Processes
表层整体再塑
（地面塌陷）
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
The surface of the land is subsiding over
wide areas near Phoenix,AZ,Houston,TX,
Fresno,CA,as well as at other parts of the
world such as Tokyo,Mexico City,London,
and Venice,This subsidence is caused by
the withdrawal of large volumes of ground
water from unconsolidated sediments,
Land subsidence also occurs due to the
solution of soluble rocks; in some cases,
this subsidence may be triggered by man,
Land subsidence may also occur over
mined land.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Land Subsidence Due to Withdrawal of Fluids
Subsidence due to ground-water withdrawal
develops under two contrasting environments and
mechanics,The most extensive occurrence is in
unconsolidated to semiconsolidated sediments
containing confined or semi-confined sand and gravel
aquifers含水层 interbedded with clayey aquitards隔水
层, Another occurrence is in soluble rocks containing
caves or sinkhole deposits; a lowered water table may
cause erosion of cave fill or cave collapse due to loss
of buoyant support from ground water.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
Extensive land subsidence is caused by the withdrawal of
fluids (e.g.,ground water or petroleum) from weakly
consolidated artesian承压 aquifers,The key to
understanding this phenomena is the concept of aquifer
elasticity,Fig9.1 illustrates how the total stress
(lithostatic岩石静压 overburden过载 ) on an aquifer (St) is
supported by stress on the grain-to-grain skeleton of the
aquifer (effective stress = Sk ) as well as the water
pressure in the aquifer (Sw ):
(2.3.1)
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Mechanism
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
San Joaquin Valley,CA,California has a greater area
affected by land subsidence than any other state,The
southern part of the Great Valley,California,is intensely
irrigated by ground water,At least 11,000 km2 of this
important agricultural area has subsided more than 0.3 m
since the 1920s creating the world's largest area of intense
land subsidence,According to Poland et al,(1975),an area
113 km long has subsided more than 3 m,with a maximum
of 8.5 m,(Fig9.3) The volume of subsidence amounts to 20
km3 or about half the volume of the Great Salt Lake.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
In 1982 the U.S,Geological Survey studied
movement of growth faults (Fig.9.5) and found that
seven monitored faults in the area of water level
recovery had stopped moving,By contrast,the five
monitored faults in the area where water level has
continued to drop have displacements averaging 1
cm/yr.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Wilmington oil field petroleum
withdrawal at the Wilmington oil
field has caused enormous land
subsidence along the Pacific coast
at Long Beach,CA,The U.S,Navy
shipyards have subsided up to 9m
causing the shipyard to sink below
sea level (Fig.9.10),this required
the $ 100 million construction of
levees大堤 and sea walls to keep
the Pacific from inundating淹没 the
shipyard,Apparently,the
subsidence has been stopped by
injecting salt water into the oil-
bearing formations to restore fluid
pressure.
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
Wilmington oil field
Small,local subsidence
problems associated with
petroleum extraction has
been known for some time,
In some places,flowing
sand moves up the well
casing,resulting in local
ground subsidence,
Historical faulting at
southern California oil fields
may be related to oil-field
development rather than
deep tectonic forces
Part three 地球表层的塑造过程
环境地质学 Environmental Geology
Land Subsidence
Examples of Land Subsidence
wkt SSS ??
