relationships :: essays research papers

The position of thrust rag weeks aroundthe margins of landslide walk forfends, and theirmorphology and direction of thrusting, suggests thatthey were formed as a proceeds of walk block pressure sensation and performance in the surrounding rachis. Toe-thrust sheets thus can be considered as the morphologicalexpression of ongoing instability at the landslidetoe. The upthrust nature of these sheets at WestRunton suggests that rotation of toe blocks,generating forward movement of the surrounding loosebeach gritstone, is the principal process of toe-thrustsheet formation (fig. 6). Passive crush of toeblocks into the surrounding common sense under gravity isunlikely to result in either brittle failure of thesand or differential movement of the sand away fromthe toe blocks (i.e., different thrust sheet widths).The presence of thrust sheets therefore suggests thatlandslide blocks are actively excavating into thesofter and unconsolidated beach sand that is displacedoutward as a re sult of this process. The size and extent of the thrust sheets can be usedas a proxy for the scale, rate, and timing of blockmovement. For example, the bigger landslide blocks areassociated with more extensive thrust sheets, andsheet width is likely associated with excavationdepth. The presence of aggregate and overlapping thrustsheets that digress in extent along the front oflandslide blocks (figs. 4, 5) also suggests thatdifferent parts of the toe are active at differenttimes and therefore that sliding rates and volumesaveraged across the entire landslide (Waltham andDixon 2000) likely conceal wide spatial and temporalvariations. Graphic omitted The presence of fragile toe-thrustsheets in spite of appearance the intertidal geographical zone at West Runton is ofinterest because these features are easily destroyedby waves and will be wiped out by every(prenominal) high soar upwards.Figure 6 is a schematic cartoon illustrating apossible formation mechanism for these features.Du ring high tides, the elevated position of the outer weewee plane (mean high weewee level) againstthe landslide toe means that there is a smalldifference in head, and low hydraulic potentialgradient, amongst the landslide toe and its externalenvironment (fig. 6a). The depth of marine wet alsolikely increases interstitial pore water pressure bothwithin the submerged beach sand and within thefine-grained landslide sediments and influenceseffective pressure (cf. Dixon and Bromhead 2002).Elevated external water pressure at high tide helps tohold back toe advance (Hutchinson 1988). At low tide, when the ground water table is locatedwithin the beach sand and is under impose (atmospheric)interstitial pore water pressure, a large differencein head and therefore steepened hydraulic potentialgradient exists between the landslide toe and theexternal environment (sea level) (fig. 6b). netherthese conditions, sliding and the formation ofrelationships essays research papers The position of thrust sheets aroundthe margins of landslide toe blocks, and theirmorphology and direction of thrusting, suggests thatthey were formed as a result of toe block pressing andmovement in the surrounding sand. Toe-thrust sheetstherefore can be considered as the morphologicalexpression of ongoing instability at the landslidetoe. The upthrust nature of these sheets at WestRunton suggests that rotation of toe blocks,generating forward movement of the surrounding loosebeach sand, is the principal process of toe-thrustsheet formation (fig. 6). Passive pressing of toeblocks into the surrounding sand under gravity isunlikely to result in either brittle failure of thesand or differential movement of the sand away fromthe toe blocks (i.e., different thrust sheet widths).The presence of thrust sheets therefore suggests thatlandslide blocks are actively excavating into thesofter and unconsolidated beach sand that is displacedoutward as a result of this process. The size and extent of the thrust s heets can be usedas a proxy for the scale, rate, and timing of blockmovement. For example, the bigger landslide blocks areassociated with more extensive thrust sheets, andsheet width is likely associated with excavationdepth. The presence of multiple and overlapping thrustsheets that vary in extent along the front oflandslide blocks (figs. 4, 5) also suggests thatdifferent parts of the toe are active at differenttimes and therefore that sliding rates and volumesaveraged across the entire landslide (Waltham andDixon 2000) likely conceal wide spatial and temporalvariations. Graphic omitted The presence of delicate toe-thrustsheets within the intertidal zone at West Runton is ofinterest because these features are easily destroyedby waves and will be wiped out by every high tide.Figure 6 is a schematic cartoon illustrating apossible formation mechanism for these features.During high tides, the elevated position of theexternal water plane (mean high water level) againstthe landslide toe means that there is a smalldifference in head, and low hydraulic potentialgradient, between the landslide toe and its externalenvironment (fig. 6a). The depth of marine water alsolikely increases interstitial pore water pressure bothwithin the submerged beach sand and within thefine-grained landslide sediments and influenceseffective pressure (cf. Dixon and Bromhead 2002).Elevated external water pressure at high tide helps tohold back toe advance (Hutchinson 1988). At low tide, when the ground water table is locatedwithin the beach sand and is under lower (atmospheric)interstitial pore water pressure, a large differencein head and therefore steepened hydraulic potentialgradient exists between the landslide toe and theexternal environment (sea level) (fig. 6b). Underthese conditions, sliding and the formation of