Sand boils

Numerous sand boils (10-30 ft in diameter, sometimes coalescing in ridges) were observed along fractures depositing between 4 and 12 inches of material from depths of 25 to 75 ft. Settlements up to 3.5 ft were noted Bridge piers rotated owing to high lateral Ross et al. 

Large slide occurred along bluff. Size was 8500 ft long and extended back 600 to 1200 ft. Ground dropped about 35 ft. Lenses in clay believed to have liquefied. As bank failed, the slide progressed back. Sliding surface defined at about 60 ft below the surface. Slope of slide was about 4%. Sensitivity of the clay contributed to the scale of occurrence. Ridges of sand boils noted. One boil spread over 3200 ft area... 

Settlements from less than 1 ft to several feet occurred in areas subjected to slumping and sliding as excess pore pressures dissipated. Nearly all major valleys in south central Alaska showed evidence of fissmes and flows. Numerous sand boils occinred depositing material in cones, and (2-3 ft high and 100 ft long) ridges up to 6 ft wide and in one case a 1-acre area 3 ft deep. The sand in one cone was reportedly pumped from a depth of 12 ft... 

Qualitative description of settlement, sliding and sand boils that occurred in the zoological gardens... 

Crest of dam moved downstream about 5 ft and settled about 3 ft. Entire dam moved. Believed part of movement due to liquefaction or partial liquefaction. No well-defined slip surface and several sand boils at downstream face. Slide believed to have occurred near end or after strong shaking... 

Sand boils commonly formed below scarps (gives location of 25 such features) slides are attributed by partial or complete liquefaction ... 

Fernando failures at the upper and lower San Fernando dams. In general, a combination of fine-grained soil and a high water table resulted in the formation of sand boils and reported submerged sand boils in zones up to 200 ft wide. Materials in boils ... 

Sand boils, fissures, and spouts of sands and silts are observed. Lateral spweading landslides observed at river banks (Ashely River) and raQroad tracks (Rantoules)... 

Sand boils up to 2 ft in diameter were observed along beach Site involved in a lateral spreading landslide. Slumping and fissuring of ground accompanied by some movement toward lake. Horizontal movement only several feet Three large flow slides occurred on the valley sides of the San Pedro River. Volumes of slide material were 40 X 10 8 X 10 and 3 X10 ydL Sliding distance was as much as 1000 ft... 

Liquefaction along coastal areas resulting in uniform settlement of structures, landslides into ocean, and sand boils... 

Sand boils consisting of medium coarse sand from 5 to 9 ft depth observed in addition to extensive lateral spreading... 

Venting occurred along induced fracturing or zone of weakness. Sand boils surface expression maybe either elongated or approximately circular in shape. Sand boil typically starts 2-3 minutes after end of earthquake and will last up to 1 h. 

Can occur under water. Maximum depth of material for sand boils originated at 66 ft (20 m)... 

Wave loading along coast. Note Sand boils can occur in slide zone. 

Jordan, K. 1984. Modelling sand boils observed during the November 1980 Humboldt earthquake. Thesis presented in partial ftilfillment of the requirements for degree of Bachelor of Science in Environmental Resources Engineering, Humboldt State University, Areata, CA. 

Ridges of sand 2 to 3 ft high and 3 to 6 ft wide by 100 ft long were formed by sand boils within the slide area. One such boil covering a 3200 fh area was reported... 

Many sites liquefied that had previously liquefied during Mino-Owari earthquake Sand boils, fissures and quick conditions encormtered... 

Caused liquefaction in coastal regions where soft alluvial deposits occtir. In east seven different sites involved. Settling and tilting of wooden houses recorded. Large quantities of sand and water ejected from sand boils... 

Figure 6. Liquefaction induced sand boils at the bridge site...

The foundation soil at the site of the plate girder bridge showed signs of liquefaction, as indicated bythe sand boils seen in Figure 6. The plate girder bridge introdueed earlier, suffered some rotation... 

Figure 3. Photos of sand boiling in Wenchuan earthquake, (a) The sand cover the land (b) the sand boiling in YanTing County (by Deng Zhihui).

There are at least 3 processes of the sand liquefaction outcroped to the ground surface, partial sand liquefaction, whole sand liquefaction and the spouting out of liquefied substance, i.e. the sand boiling. Whether these three processes can be completed and the time they cost basically depends on the mechanical and geometrical properties of the... 

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