Suspect Board by Lucas Leung

Suspects

ps20143163 — 2021-03-17 11:24:31 UTC

The Shum Wan Road Landslide struck at 4:00a.m., on the 13th of August 1995

Human Causes

ps20143163 — 2021-03-17 11:24:38 UTC

Natural Causes

ps20143163 — 2021-03-17 11:25:02 UTC

Typhoon Helen

ps20143163 — 2021-03-17 11:27:03 UTC

- Formed on August 7th, 1200 Km east of Manila - August 11, Typhoon Helen intensified into a typhoon - Typhoon Helen made landfall about 60km northeast of Hong Kong. - On August 13, Typhoon Helen rapidly weakened and dissipated.

Wet Soil

ps20143163 — 2021-03-17 11:31:06 UTC

- Heavy precipitation was measured in the two rainfall gauges, H20 and H05.
- Both had measured extremely high intensities of rainfall periods
- The water may have caused the soil to be wet, which increases the weight and reduces the friction of the soil.

Construction & Architecture

ps20143163 — 2021-03-17 11:37:17 UTC

Apart from the road, there were also a school-building project nearby - the construction of CDNIS, our neighbouring school, Canadian International School of Hong Kong. Their construction has started on 1991, a slight four years before the disaster took place. This may have contributed to the event of the landslide as when construction, there will be lots of big vibrations of machines and heavy materials being imported for the construction. The vibration may have loosened the soil and dirt, and the materials being heavy may have increased the burden of the soil.

Water pipes

ps20143163 — 2021-03-17 11:38:02 UTC

As seen in the graph below, there are water pipes positioned very near, and one of them on the landslide site. This may have contributed to the landslide because if the pipes have leaked, the water would create wet soil, increasing the weight and decreasing the friction of the soil, and hence increasing the chance of a landslide happening.

Dense Vegetation

ps20143163 — 2021-03-17 11:44:34 UTC

- As mentioned from the witness, the hill was covered in trees.
- It is a possibility that these trees are heavy in weight, but they are still young and their roots are not deep enough.
- If this is the case, vegetation may be adding weight onto the hill instead of steadying the soil with the roots

Slope angle

ps20143163 — 2021-03-21 07:18:23 UTC

- The angle of the slope affects the gravitational pull of the soil towards the earth.
- If the angle of the slope is too big, the soil would go down the hill.
- In this case, the soil used to be 27º, which calculates to about a 50.95 slope %. Landslides usually occur in percentages of 30+, which increases in probability as the percentage increases.

Soil erosion

lucasleung517 — 2021-03-25 12:12:40 UTC

- There was evidence of landslips or soil erosion near the site since the 1940s.
- Mainly concentrated on the banks along Nam Long Shan road.
- The soil erosions are directly above the retaining walls, which is also where the landslide started