First seismic T-Phase events for 2015

  • #1


Science Advisor
Gold Member
hi everyone,
Well we are into a new year and into new discoveries and observations

Yesterday morning, Jan 6th, 0548NZST ( 05 Jan 1748UT) there was a reasonable quake in the mountains of the central South Island of New Zealand M 6.0 GNZ ( M 5.6 USGS). Now the quake itself isn't unusual, NZ is prone to regular quakes because of its location straddling the Indo-Australian Plate and Pacific Plate boundary.
What was unusual is that this is the first time I have seen/recorded T-phase waves from an inland event.
All previous events have been under the seafloor, see previous thread ...

This first image is of the long period seismogram to show the overall quake. The T-phase is not identifiable in this image as it is buried in amongst the surface waves

150105 174842UT M5.6 ( 6.0GNS) Sth Is event with T-phase1.jpg

This second image shows the P wave arrival at 1752UT and the T-Phase arriving at ~ 1810UT
Note its amplitude is much larger than either the P or S arrivals ( actually the S wave arrival cannot be seen)

150105 174842UT M5.6 ( 6.0GNS) Sth Is event with T-phase .jpg

The surprises that this subject of seismology is still coming up with :)

  • #2
I was going to ask about that. Been on the news for hours, and no post, I was starting to wonder.
  • #3
It was out in the middle of nowhere. Arthur's Pass would have been about the closest community, maybe Cass. I have not heard of any damage reports. Tho many closer in probably did have crockery off shelves etc

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