Central Weather Administration seismic intensity scale

The Central Weather Administration seismic intensity scale (Chinese: 交通部中央氣象署地震震度分級, CWASIS) is a seismic intensity scale used in Taiwan. It was established by the Central Weather Administration.

Scale overview

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Central Weather Administration seismic intensity scale[1][2][3]
Intensity
(震度分級)
Strong Ground Acceleration
(cm/s2,gal)
Ground Speed
(cm/s)
Effects on People Effects Indoors Effects Outdoors
0 Micro
(無感)
below 0.8 gal Not felt.
1 Very minor
(微震)
0.8-2.5 gal Felt only by a few people at rest, vibrates slightly.
2 Minor
(輕震)
2.5-8.0 gal Felt by the majority of people. Some awakened from sleeping. Hanging lamps and objects vibrate slightly. Standing vehicles vibrate slightly, similar to being passed by a truck, but only lasts for a short time.
3 Light
(弱震)
8.0-25 gal Felt by nearly everyone, a few frightened. Buildings shake; dishes, windows, and doors shake making sounds; hanging objects shake visibly. Standing vehicles vibrate obviously; electric wires sway gently.
4 Moderate
(中震)
25-80 gal less than 15 cm/s Many people are quite frightened, looking for safe shelter. Most people are awakened from sleep. Buildings rock noticeably; unstable objects topple over; heavy furniture moves; may cause slight damage. Felt by drivers; electric wires sway obviously, felt by people walking.
5 5- Strong
(強震)
80 gal and above 15–30 cm/s Most people are considerably frightened. Walls crack; heavy furniture may overturn. Noticeably felt by drivers; some chimneys and large archways topple over.
5+ 30–50 cm/s
6 6- Very strong
(烈震)
50–80 cm/s People have trouble walking due to violent rocking. Damage to some buildings; heavy furniture overturns; doors and windows bend. Drivers have trouble steering; sand and clay blasts occur.
6+ 80–140 cm/s
7 Great
(劇震)
140 cm/s and above People move with difficulty due to severe rocking. Severe damage to or collapse of some buildings; almost all furniture moves or falls down. Landslides and faults rupture occur; railway bend; underground lines break.

References

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  1. ^ "交通部中央氣象局有感地震報告發布作業要點" (PDF). 2019-12-11. Archived (PDF) from the original on 2019-12-11. Retrieved 2021-06-02.
  2. ^ 交通部中央氣象局新聞稿
  3. ^ 地震百問 震度 - Central Weather Administration