Link to USGS home page
USGS Home
Contact USGS
Search USGS
Coastal & Marine Geology InfoBank

USGS CMG InfoBank: Creep

Skip navigational links
Search InfoBank
Home tab FACS tab Activities tab Atlas tab Geology School tab More tab More tab Geology School tabs
   
Dictionaries: The USGS and Science Education   USGS Fact Sheets   Topics   Keywords   Data Dictionary   Metadata Dictionary   Computer Terminology   Digital Formats
InfoBank Terms: Activity ID   activity overview   crew   formal metadata   lines   metadata   NGDC   port stops   project/theme   region   ship   stations   time   virtual globe   year  
Data Types: bathymetry   geodetic positioning   gravity   ground penetrating radar   imagery   LIDAR   magnetics   metering equipment   navigation   samples   seismic   definitions disclaimer  
Data Formats: ARC coverage   E00   FGDC metadata   gridded/image   imaging   material   scattered/swath   Shapefile   vector/polygon  
   
Comment: 05:33 - 06:57 (01:24)

Source: Annenberg/CPB Resources - Earth Revealed - 16. Mass Wasting

Keywords: "mass wasting", creep, slope, soil, bedrock, gravity, water, season, Alaska, freeze, thaw, "geologic hazard"

Our transcription: At first glance, for example, this site appears tranquil and undisturbed, but a closer look reveals the presence of "creep," a sluggish form of mass wasting that sometimes moves as slowly as one centimeter per year.

Creep operates every day, everywhere, no matter how gentle the slope.

Creep occurs when the soil and uppermost part of the bedrock within a slope moves slowly downhill under the influence of gravity and water.

The wetting and drying of the uppermost ground material results in alternate expansion and contraction with gravity pulling the contracting Earth imperceptibly down slope.

This can happen even when the angle of the slope itself is very small, almost to the point of being horizontal.

Creep is especially active in regions where moist ground seasonally freezes and thaws, such as here in Alaska.

Each freeze thaw cycle moves soil particles downhill in minute increments.

And despite the fact that no one has ever died from creep, it does more long term economic damage than all other forms of mass wasting combined.

This can take the form of buckling railroad tracks or cracked building foundations, as well as broken underground water and sewer lines.

Geology School Keywords

Skip footer navigational links


InfoBank   Menlo Park & Santa Cruz Centers   St. Petersburg Center   Woods Hole Center   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  

FirstGov button   Take Pride in America button