What is liquefaction?
Liquefaction takes place when loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking. Liquefaction occurring beneath buildings and other structures can cause major damage during earthquakes. For example, the 1964 Niigata earthquake caused widespread liquefaction in Niigata, Japan which destroyed many buildings. Also, during the 1989 Loma Prieta, California earthquake, liquefaction of the soils and debris used to fill in a lagoon caused major subsidence, fracturing, and horizontal sliding of the ground surface in the Marina district in San Francisco.
Why do earthquakes in other countries seem to cause more damage and casualties than earthquakes in the U.S.?
Just as loose lips sink ships, loose soils can create this week’s EarthWord...
New hazard maps that describe the probability of earthquake-induced liquefaction in Northern Santa Clara Valley are now available from the U.S Geological Survey (USGS.)
Two new maps give first responders, land use planners, decision makers and Bay Area residents a new and more detailed look at the risk of "liquefaction" in the soils underlaying buildings and other important components of the Bay Area infrastructure, such as roads and pipelines.
USGS Researcher Introduces New Method To Assess Potential Losses From Liquefaction During Earthquakes
A new method of assessing the danger of ground failure due to soil liquefaction during an earthquake made its debut in San Francisco, Tuesday afternoon, December 17.
Liqufaction from the 1989 Loma Prieta Earthquake in California. Credit: J. Tinsley, from U.S. Geological Survey.
The Gold Rush and the 1906 Earthquake: How they combined to create the breakthrough discovery of modern seismic science
- Accidents of Gold Rush merchant marine navigation transformed a seismic disaster into a seminal discovery and led to San Francisco's extreme liquefaction vulnerability today.
- Just about everything that we love about the Bay area is
I saw on a map that I live in an area of "high liquefaction probability." What does that mean and can I do anything about it?
Listen to hear the answer.
Ground shaking triggered liquefaction in a subsurface layer of sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and silt, which moved from right to left toward the Pajaro River. This mode of ground failure, termed "lateral spreading," is a principal cause of liquefaction-related earthquake damage.
"Sand boil" or sand volcano measuring 2 m (6.6 ft) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction). Vented sand contains-marine shell fragments.
Liquefaction in recent deposits of the Pajaro River formed sand volcanoes along a fissure 6-7 m (19.7-23 ft) long. Variation in grain size and partial erosion of the conical deposits of sand show that venting of the slurry of sand and water was a complex series of depositional and erosional events triggered by the main shock and renewed in some instances by principal...
Liquefaction in recent deposits of the Pajaro River formed these sand volcanoes along extensional fissures in a field prepared for autumn planting near Pajaro, across the Pajaro River from Watsonville. Furrows are spaced about 1.2 m (4 ft) apart.
Liquefaction in recent deposits of San Lorenzo River caused cracking and differential settling of river levee southeast of Riverside Avenue Bridge. Bridge piers and the north abutment area were also damaged by liquefaction.