Dear all,
I kindly ask under which circumstances EQs are shown on ShakeNet. German authorities reported a small EQ (please see encl.). I think that something can be seen in my data ( AM.RA52C, also encl.). What would I have to change to see an event.
Kind regards
Jürgen
andernach.pdf (187.9 KB) 
Hi Jurgen,
We are looking into this. Thanks for letting us know.
Ian
Any hint? Is my assumption correct, that data is only considered if the ground motion shows a small figure?
Sorry for the delay. The reason this event wasn’t picked up is because it did not meet our quality criteria at enough stations to be registered as an official event. Because of the nature of the network and the amount of noise we have to filter out, events below about M3 are difficult to trust. Currently our network locates and publishes about 50% of events with magnitude greater than 4.5 and 90% of events with magnitude greater than 5.0. Configuring the network to find smaller events means a lot more false positives and a lot more work to remove them. However as the network becomes denser it will automatically small events at more nodes, which will increase the detection rate.
Disappointing. From my point of view this does not correspond to the advertising for the product. Actually, there is no argument in Central Europe to buy such a device.
hello,
sorry for your disappointment. as it turns out, there are many, many reasons to buy such a device, one of them being to detect local phenomenon (mine blasts, for example). the device, itself, is a stand-alone product that can be used by its owner for any purpose(s) they want. the network, on the other hand, is a derivative product created when many, many devices are online, which is not a requirement for any owner of a Raspberry Shake to do.
thus, the network is, in fact, not guaranteed, nor so advertised in any way, to provide a “product” as a result of purchasing a Shake. in fact, event-reporting based on the Shake network does not require the purchase of a Shake product whatsoever, anyone can receive this information.
that said, it is our intent that as the network grows and densifies we will report smaller and more local events when the network conditions allow us to report accurate information. doing so before this were true would mean we risk reporting too many false positives, i.e., wrong and inaccurate information.
in the meantime, your device records all local events regardless, reported by us, anyone else, or no one, as your original post visualizes well. cross-correlating the local event catalog from the German govt., for example, to your own data-set will allow you to identify the events recorded by your device, that you can then share via your preferred social media platform.
and, with the new rsudp program recently released, you can even set up alerts in real time based on your individual data-stream, have you seen this? if not, please have a look at the post here.
cheers,
richard
It’s all about station density and event magnitude when talking location threshold. I monitor several government stations on jAmaseis (https://www.iris.edu/hq/jamaseis/) for just that reason. A good example is station ADK located on Adak Island in the Aleutian chain. It is a very quiet broadband station and detects many global and local events, but it is situated in a “desert” when talking about station density. It records many beautiful events that never make it in the USGS catalog for the same reasons that Ian mentions.
My local Shake is great for listening to the earth and seeing what shows up: earthquakes, aircraft, trucks, wind, foot traffic, etc. Kind of like a weather station (this geek has one of those too!).
Regarding the Oct 28 event: Nice quiet seismogram, clear P and S arrivals and classic spectrogram, though not very rich in the lows. Probably a very small event just from that. The S-P time is about 10 sec or less, so the event probably happened around 80 km from you. Could be a quarry blast, but the strong S wave suggests it’s an earthquake. Very cool!!!