Yuri Kim
Q1. What is the driving force for the geomorphologic evolution? How does the driving force affect the geomorphologic evolution?
The geomorphologic evolution is caused by regionaltectonic uplift and sediment transport process. The initial rapid uplift makesthe landscape high and initiates sediment erosion and transport. After stopping this uplift, sequence of soil erosion and sediment transport process change the geomorphic figure.The rate of soil erosionis affected by amount and circulation of heat, water, solutes, rock characteristics and other processes. The sediment transportdepends ontractive power of geomorphic agents, such as water flow, waves, wind etc.and soil characteristic. In combination, these various factors make transport, in other words mass wasting,rapid and huge like landslidein some cases or continuous but slow like soil creep in other cases.
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Q2. Describe the effect of the diffusivity coefficient on the geomorphologic evolution.
As time goes by,the slope of Kg = 0.4becomes rapidly dropped (Not slope but height drops) in the respect of both x and t profile and the peak height value goes to nearly zero att =1, while the case of Kg = 0.1 has relatively low slope gradient and still has an amount of peak height and rolling land shape at t = 1. These phenomena explain that if the Kg value becomes higher, the amount of sediment transport at the unit time ( i.e. soil creep) becomeslarger.This also means the geomorphologicfigure tends to be changed more rapidly by higher value of Kg .
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Q3. Plot two temporal profiles at x=0.5
According to the graphs, both similar and different characteristics exist between these two cases. At first, the peak height appeared around t = 0.2 in both cases though the values are different (because the uplift is assumed to happen at the time). The peak heightof Kg = 0.4 is around 0.053 and lower than the height of Kg = 0.1, which is around 0.073.This shows that the magnitude of land peak height which appeared during land evolution is inversely proportional to Kg.
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Q4. Compare two geomorphologic structures, and explain why they are different.
These two graphs show the different types of geomorphologic evolution. In the first figure, the impulse uplift happened for short time at early stage of land evolution. Therefore thepeak height of land also appeared in early stage of time and thenthe land becomes low and flat because of the soil creep.However, the persistent upliftcase shows thecontinuous growth of land heightuntil the end of the time boundary, t = 1,and much higher magnitude of peak height value than impulse uplift case. This happened because uplift force continuously exist since the early stage of land change. In this case the role of soil creep is negligible in the process of geomorphologic evolution. It depends on the relative strengths between the uplift and soil creep. In this case, the uplift rate is higher than the rate of soil creep.
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11.5/12 = 9.6 Good.
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