Lake Merced      Because liquefaction only occurs in saturated soil, its effects are most commonly observed in low-lying areas near bodies of water such as rivers, lakes, bays, and oceans. The effects of liquefaction may include major sliding of soil toward the body Motagua River slumping and of water, as in the case of the 1957 Lake Merced slide shown above, or more modest movements that produce tension cracks such as those on the banks of the Motagua River following the 1976 Guatemala Earthquake.

     Port and wharf facilities are often located in areas susceptible to liquefaction, and many have been damaged by liquefaction in past earthquakes. Most ports and wharves have major retaining structures, or quay walls, to allow large ships to moor adjacent to flat cargo handling areas. When the soil behind and/or beneath such a wall liquefies, the pressure it exerts on the wall can increase greatly - enough to cause the wall to slide and/or tilt toward the water. As illustrated below, liquefaction caused major damage to port facilities in Kobe, Japan in the 1995 Hyogo-ken Nanbu earthquake.

Portdamage, Kobe 95 Retaining wall damage and lateral spreading, Kobe 1995.(KG) Portdamage, Kobe 95 Lateral displacement of a quay wall on Port Island, Kobe 1995.(KG)
Portdamage, Kobe 95 Lateral spreading caused 1.2-2 meter drop of paved surface and local flooding, Kobe 1995.(KG)

Port damage, Kobe 95 Damaged quay walls and port facilities on Rokko Island. Quay walls have been pushed outward by 2 to 3 meters with 3 to 4 meters deep depressed areas called grabens forming behind the walls, Kobe 1995.(KG)

Collapsed bridge, Niigata 64      Liquefaction also frequently causes damage to bridges that cross rivers and other bodies of water. Such damage can have drastic consequences, impeding emergency response and rescue operations in the short term and causing significant economic loss from business disruption in the longer term. Buckled bridge, Tokachi 1948 Liquefaction-induced soil movements can push foundations out of place to the point where bridge spans loose support (above, SC) or are compressed to the point of buckling (left, SC).

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