Natural disasters associated with land use changes and community growth is becom

Question

Natural disasters associated with land use changes and community growth is becoming more frequent in many regions of the world. A large percentage of the damage to property and loss of life is related to ignorance of local geologic and environmental risk factors resulting in uninformed building site choices. Watch the following video footage from the 2003 Devore, CA disaster by cutting and pasting the following link into your web browser (https://www.youtube.com/watch?v=k3W-wDIR-Os).

1.) How would you characterize the natural disaster in Devore, CA from the images you saw? Consider what the dominant mechanism must have been to generate the level of damage observed. You may want to refer to Chapter 12 in the book for ideas and/or clarification.

2.) Describe the maximum, minimum, and average (approximate) clast size being moved in the video. (Refer to the clast size designations we used in lecture as a guide.) What is the relationship between clast size and the energy required to overcome the coefficient of static friction? (Don’t worry, you can keep it simple here…)

3.) What types of environmental conditions could contribute to the intensity of this event? (Consider the various components of hillslope stability from Chapter 12). What steps could have been taken (if any) to help mitigate this disaster? (Be creative, there are many ways to approach this problem…)

Explanation / Answer

yes , this is right that natrural disaster events and loss of life has been increased from last two decade because of the ignorance of geologic and environmental risk factors.in this video, we can see that this is the debris flow which occured after the heavy rainfall.

1. debris flow happened at 25 december 2003 in devore, CA, reason behind this debris flow can-

A) wildfires, as we can see in the video that they mention that wildfire raged across the mountains and hills od south california, name of the wildfires are old and grand prix in areas adjacent to cajon pass . this fires destruct all forest around the devore. we very well know that trees are capable to bound soil togeather witrh the help of its roots. but when they burned soil and regolith has been free from the roots and flows with the rain water to the devor.

B) may be this village is located at the wrong place . i mean that may be this area was the runoff area several time ago or its a path of a seasonal river but for a long time seasonal river not get sufficient water to flow so people think that its a normal place but this time when heavy rainfall occurs river get a much of amount of water and flows and get debris with it which present at the path of the river.

2. we can see here , boulders also carried by the water , and water color is so dark so we can can also in the water clay silt and sand . so we can conclude that clast size of the debris minimum 0.98 mu meter and maximum 256 mm and average 1.26 to 2.55 mm.

clast size is directly proportional to the energy required to overcome the coefficient of static friction static friction is oppose the force to remove the substance. and static friction increased with the clast size.

3. wild fires and heavy rainfall are the two main reasons who are responsible ro icreased intensity of debris flow. because roots of the trees are capable to bound soil togeather and heavy rainfall gives the direction to these debris.

there is some precautions which taken by the government and local people for the next debris flow event.

A) plant trees at the burned areas which will helpful to decrease the intensity of the debris flow and landslides

B) identify the areas of runoff and do not construct any structure in the path of the runoff.

C). if possible , they should remove from that area because in future it can be worse.

D) trained them by the naturalo disaster team to survive in these type of conditionbs.

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.