6.8 and 6.9 are both right, just different unit.

Also, another thing: why does an earthquake often have an initial magnitude that then changes over time? Like I think the initial ping for this was a 7.2, like take a look at this prelim from USGS:

https://twitter.com/USGSted/status/1571394895075500032

How can it be OoM off at first?

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...

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

https://earthquake.usgs.gov/earthquakes/eventpage/us7000i90q...

You can see on the shakemap Taipei has an MMI of close to 4, which corresponds to: "Felt indoors by many, outdoors by few during the day: At night, some are awakened. Dishes, windows, and doors are disturbed; walls make cracking sounds. Sensations are like a heavy truck striking a building. Standing motor cars are rocked noticeably."

The intensity scale on the other hand measures the amount of shaking for a given location. Naturally, the further you are from the epicenter, the lower the intensity will be.

It's quite confusing to have a couple of different numbers to "characterize" a quake: magnitude (in a few different systems), intensity scale (guess there are different systems around the world as well).

Really great to see the clarity here from knowledgable people on this! :) ;pxx ;p

Magnitudes 6-7 were in the epicenter near Taitung, fairly far away - about 200-300km

Haha I'm well aware of that. I'm not saying that's not the case I'm saying in another comment that the shaking that I felt, I felt sickening. What you say doesn't contradict what I'm saying

Just disagreeing for the sake of it? Stupid and abusive.

The recording of 6.9 was made hundreds of kilometres away from Taipei. What was felt at Taipei 101 was a much lower magnitude.

No, this is a confusion.

Read the other comments here: there's two things (which I just learned from reading this, but I always knew the epicenter magnitude is the measure of quake power):

1. The recorded magnitude for a quake is the measure of energy of quake at that epicenter.

2. An intensity scale measures the shaking (and it's perceptual effects on humans) at distances from the epicenter.

Stop contesting what I'm saying here: I'm saying the magnitude was 6.9. That's a true statement.

I'm also saying I fucking felt it. That's also true. Stop telling me I got either of those things wrong. They're both true. You don't fucking know what I felt or what I didn't feel. Also, the magnitude was 6.9 (or 6.8 depending on system used).

Obviously I know that what you feel a further distance from it is less shaking that what you feel up close. Come on, of course! It's obvious. Why assume I'm saying something "dumb", or can't understand that unless you need to pretend to look down. And why assume that what I'm saying is false; I'm saying that what I felt in Taipei was sickening. You can't question! That's what I fucking felt.

You have no idea of what I felt. You can't question it. Jeeus F Christ, what is wrong with you?

Ok, maybe you weren't saying that specifically...but you know what I mean? People on here trying to tell me I had magnitude wrong: no I had it 100% right. Trying to tell me what I could or couldn't feel, not they can't. Trying to be like surprised I felt sickening at this: it's my fucking reaction. I can feel whatever I want and you have no idea about that and no say in that.

It's a basic question and boundary. My feelings and reactions are what I know and no one else can tell me that something internal to me didn't happen, and I experienced it, and I know it happened.

I mean can you understand how exasperating that is? It's like: "You people don't have any idea at all, what are you even talking about?" Ugh.

But, today i learned I can abuse someone by telling them how they feel.. New worlds of opportunity have opened up.