Potential Debris Flow Gully and its Discrimination — A Case Study in Wenchuan Earthquake Hit Areas

2012 ◽  
Vol 518-523 ◽  
pp. 4620-4625
Author(s):  
Xing Zhang Chen ◽  
Yong You ◽  
Jin Feng Liu
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Disaster Prevention ◽  
Analysis Method ◽  
Discrimination Analysis ◽  
Linear Discrimination ◽  
Discrimination Model ◽  
Linear Discrimination Analysis ◽  
Evolution Phase

In this paper, we firstly defined the potential debris flow gully. And then using the data of different gullies in Wenchuan earthquake hit areas, we built a discrimination model of potential debris flow gully by Fisher Linear Discrimination Analysis method. Finally, the model was used to discriminate the gullies in Jinxihe catchment, in Anxian County. Potential debris flow gully is a kind of special gully which is in a special evolution phase of the gully when the gully has the happening possibilities of debris flow but no debris flow records. Because potential debris flow can often pose more serious disasters, discrimination of potential debris flow gully is important for disaster prevention and mitigation. To build discrimination model of potential debris flow gully, a database of different gullies in quake-hit areas was established and six discrimination indices were selected based on cause analysis of debris flow. Using the database and the six discrimination indices, we built the discrimination model by Fisher Linear Discrimination Analysis method. The discrimination model was used to discriminate the gullies in Jinxihe catchment. Discrimination results showed that the discrimination model was effective and feasible in discriminating potential debris flow gullies, but it still needs further revised and perfected.

Fluorescence array-based sensing of nitroaromatics using conjugated polyelectrolytes

The Analyst ◽  
2016 ◽  
Vol 141 (11) ◽  
pp. 3242-3245 ◽  
Author(s):  
Jiatao Wu ◽  
Chunyan Tan ◽  
Zhifang Chen ◽  
Yu Zong Chen ◽  
Ying Tan ◽  
...  
Keyword(s):  
Sensor Array ◽  
Conjugated Polyelectrolytes ◽  
Discrimination Analysis ◽  
Linear Discrimination ◽  
Linear Discrimination Analysis

A sensor array consisting of six conjugated polyelectrolytes was constructed to discriminate between nine nitroaromatics by linear discrimination analysis.

Disaster prevention education through learning about past heavy rainfall and debris flow damage

2020 ◽  
Author(s):  
Banshoya Shogo
Keyword(s):  
High School Students ◽  
Debris Flow ◽  
Heavy Rainfall ◽  
Heavy Rain ◽  
Aerial Photographs ◽  
Disaster Prevention ◽  
School Students ◽  
Prevention Education ◽  
The Past

<p>This study is an introduction to disaster prevention education for high school students, which aims to raise disaster prevention awareness by learning about disasters that occurred in the past. We live in Hiroshima, Japan. There are many fan-shaped regions in this area, and when heavy rain falls due to the rainy season or typhoons, it is easy for debris flow disasters to occur. The most recent damage was caused by a heavy rain in July 2018. On July 7, 2018, 250 to 300 mm of rain fell in one day. As a result, debris flow damage occurred, greatly affecting the students’ life. Debris flow damage is said to occur repeatedly in the same place. Therefore, I think that learning from the past damage will help students learn about future disaster prevention. </p><p>My students have studied the following 1 and 2 since April 2019. And we worked with graduate student and a professor at Hiroshima University.</p><p>1: Case study of debris flow damage caused by a typhoon (Makurazaki-typhoon) that occurred in 1945.</p><p>A huge typhoon occurred in September 1945, causing heavy rainfall and a debris flow disaster. Then our area was very confused. (Because, just after the war, only one month had passed since the atomic bomb was dropped). Therefore, details of the debris flow damage caused by the typhoon are not known.</p><p>So, we analyzed the aerial photographs taken after the disaster and clarified the extent of the damage. We examined the Kirikushi district in Etajima City, Hiroshima Prefecture, Japan as a case area.</p><p> </p><p>2: Case study of debris flow damage through fieldwork.</p><p>We went to the area we studied in 1. We talked with people who were once affected by debris flow damage in 1945.<span>  </span>As a result, we were able to clarify the situation immediately after the occurrence of debris flow.<span>  </span>And we also asked about the debris flow damage in 2018 and compared the two damages.</p>

IMPACT OF EARTHQUAKE ON DEBRIS FLOWS — A CASE STUDY ON THE WENCHUAN EARTHQUAKE

2011 ◽  
Vol 05 (05) ◽  
pp. 493-508 ◽  
Author(s):  
NING-SHENG CHEN ◽  
GUI-SHENG HU ◽  
MING-FENG DENG ◽  
WEI ZHOU ◽  
CHENG-LIN YANG ◽  
...  
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Key Factors ◽  
Land Form ◽  
Earthquakes In China ◽  
The Impact ◽  
Debris Flow Initiation ◽  
Stable Stage

This paper describes a study about the impact of earthquakes on debris flows with a focus on the Great Wenchuan Earthquake 2008 in China. The land form, precipitation, and source material are the three key factors for debris flow initiation in the Wenchuan surrounding area. Classifications and examples of four types of debris flow initiation triggering (gully triggering, slope triggering, liquefaction triggering, and gully erosion triggering) have been presented. The initiation mechanisms are attributed to hydraulic and geomechanical aspects. The actual debris flow cases linked with the Great Wenchuan Earthquake and other earthquakes in China have been used to illustrate the increased magnitudes of debris flows due to a large amount of loose materials created by the seismic actions. The critical precipitation for debris flows is reduced by the earthquake. It is predicted that the impact of the Great Wenchuan Earthquake on the local debris flows would be significant in the next 5–6 years, and much less in the following years (up to 20 years). Finally, the debris flow system will reach a relative stable stage. This prediction is based on the historical observations at other earthquake areas and the qualitative analysis on debris flow initiation mechanisms.

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