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by alisonatwork 1371 days ago
There seems to be a bit of confusion in this thread between differing seismic scales.

The Central Weather Bureau in Taiwan uses an intensity scale where a value of 2 means the event is noticeable by most people and 3 means some of those people are frightened.[0]

For example, here[1] is the recent report for this morning's "5-" event (#137), which I can assure you everybody in the office still felt in Taipei, where it was only a "2". This event also had a magnitude of 5.9 on the ML scale that is used internationally.[2]

[0] https://en.wikipedia.org/wiki/Central_Weather_Bureau_seismic...

[1] https://www.cwb.gov.tw/V8/E/E/EQ/EQ111137-0919-100745.html

[2] https://scweb.cwb.gov.tw/en-us/earthquake/details/EE20220919...

2 comments

Seismic magnitude and intensity are two different measures.

Magnitude measures the amount of energy released by the ground movement. It is a property of the earthquake and is independent of where the measurements are taken. When someone says 'a magnitude 7 EQ', this what they are referring to. Today, the Moment Magnitude scale is used, which is a better version of the Richter scale.[1]

Intensity is a measure of the effects of an earthquake in a particular location. Intensity is commonly assessed with the Modified Mercalli Intensity scale[2], which is a qualitative measure of how the shaking was felt and what damage was done. (As an aside, since it is qualitative, it is the starting point for assessing the size of historical earthquakes.)

[1] https://www.usgs.gov/faqs/moment-magnitude-richter-scale-wha...

[2] https://www.usgs.gov/media/images/earthquake-intensity-scale

This is great, thanks! :) ;p xx ;p