EMSC Map as a research tool?

Hi, I have the EMSC global map as my home page, it is such a good site, thanks!
Each day I check to see what the Earth is up to and note the ‘total’ number of quakes - it is usually between 20-40, only very rarely lower (<5%? not verified!). The number rises greatly in response to specific swarms and when numerous aftershocks follow a single main quake. So my questions are:
Is the 20-40 M4+ quakes per day range significant? Are there known (frequency) patterns in the global system / different plate boundary areas?
Is there a way of filtering out the swarm / aftershock quakes to see if one earthquake (presumably very large ones mainly) triggers others - either nearby or even further afield - I think they do (eg the current series in Kermadec / NZ), but seem to remember reading before that they are not thought to actually do this.
Thanks and regards, Dave

I guess it’s always a tricky question to know whether the number of earthquakes is generally constant or not.
I beleive it is on a middle or long term but indeed it can vary a bit on a short term depending on aftershocks etc.

Moreover, it may also depend on the sensors… the more sensors we globally install, the more earthquakes we may be able to detect!

Dear DAC, thank you for your question and interest.
Indeed on the EMSC website ou can’t really filter out the swarm because we can’t say which earthquakes triggered which ones. The only thing you can do is filter per area and then you’ll get only earthquake in the New zealand region for instance.

I hope that at least partly answer your question, do not hesitate if you have additional ones:-)

Many thanks for the response.
From first principles u would think that the number of earthquakes is linked to how quickly strain is building within the active fault systems (or indeed currently inactive ones). This would likely be highly variable (almost random) and produce a very wide range of daily quake numbers - even if u use a magnitude filter (as the current map does). This doesn’t appear to be the case in practice, with a much more uniform daily rate than I was expecting before I started watching the map in any detail. I accept you need to allow for swarms and traditional aftershock series, which gives the appearance of clustering and is superimposed on any ‘daily baseline’ - I don’t feel able to attack this more systematically / mathematically, hence asking if anyone else had! Nevertheless, I continue to look forward to reviewing the global map at least once a day and wonder what might come next!


Thanks for the response.
Is the webpage listing available as a spreadsheet? Or can I just copy and paste the webpage into one? Would always acknowledge the data-source and it is just for my personal interest at this stage!
Rgds Dave


You can download data about the 50 last earthquake here : Latest Earthquakes Feeds - Earthquake KML/RSS Feeds

I hope this helps :wink:

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