Hi Rick,
Data is available from our fdsnws-dataselect service (
http://service.iris.edu/fdsnws/dataselect/1/) as soon as it is written to the data collection buffers. Most of the near-real-time latency is due to packetizing the data in the miniSEED format where the primary factor is sample rate, the next factor is probably compressibility. In general, the higher the data rate the faster records are filled and written to the collection buffer and available. Data recorded at 40 samples/second is commonly available within 20-60s of seconds of current time.
Most of the incoming data streams are also available from our SeedLink streaming service with the same latency governors described above:
http://ds.iris.edu/ds/nodes/dmc/services/seedlink/
Keep in mind that very low latency data is not the DMC's gig, i.e. not part of our mission. That being said we do the best we can to make data available as soon as we get it. Most data actively flowing to the DMC is available within minutes and that satisfies the vast majority of use cases, with earthquake early warning being an obvious exception.
Chad
On Jan 28, 2016, at 2:53 PM, Rick DeWitt <dewitt.rick<at>gmail.com> wrote:
Chad,
Following on John's question, which IRIS service provides the smallest latency between the time when the earth starts shaking the instrument and the availability of the data via IRIS? I'd like to explore that near-real-time realm.
Thanks,
Rick DeWitt
On Thu, Jan 28, 2016 at 1:38 PM, Chad Trabant <chad<at>iris.washington.edu <chad<at>iris.washington.edu>> wrote:
Hi John,
First, the DMC's event web service will be reduced in functionality in the near future and retired in the longer future. More on this in the next email.
But for now here are some hand-wavy ballpark numbers:
Event information from the USGS/NEIC PDE is loaded within minutes.
The ISC catalog is loaded in between 1 and 2 years behind real time
Chad
On Jan 28, 2016, at 1:19 PM, John West <john.d.west<at>asu.edu <john.d.west<at>asu.edu>> wrote:
Approximately how long does it take between when a seismic event occurs and when it appears on the event service? I'm sure it depends on which catalog reports it and possibly on size, but some ballpark number would be useful to know.
Thanks!
-- John
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John West
Chad Trabant
Rick DeWitt
Philip Crotwell
