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hi everyone
this evening a sizeable and shallow M6.6 quake SSW of the South Is. of NZ has produced
the largest T-phase event I have so far recorded on my seismic system
M 6.6 - 198km NW of Auckland Island, New Zealand
Time: 2017-07-11 07:00:01 (UTC)
Location: 49.546°S 164.031°E
Depth: 10.0 km
Location map
Long period seismogram
one of the short period sensors, a 4.5 Hz geophone
this shows the labelled P and S wave arrivals followed by the very large amplitude T-phase wave arrival at around 07:22 UT
I have shared a number of posts showing recordings of T-phase events over recent years
but this one, to coin a phrase, blows all of them out of the water"
As a reminder and also info to new comers to my posts
The T-phase waves are ones that leave the seafloor at a point roughly above the quake focus and
then travel through a deep sea path till, as in this case, they hit the continental shelf offshore of the east coast of Australia and then travel the last ~ 15 km through the ground to my recording equipment.
The T waves travel much slower than the P and S waves and hence the considerable delay in their arrival, in this case, some 18 minutes after the P wave arrival.
Regards
Dave
this evening a sizeable and shallow M6.6 quake SSW of the South Is. of NZ has produced
the largest T-phase event I have so far recorded on my seismic system
M 6.6 - 198km NW of Auckland Island, New Zealand
Time: 2017-07-11 07:00:01 (UTC)
Location: 49.546°S 164.031°E
Depth: 10.0 km
Location map
Long period seismogram
one of the short period sensors, a 4.5 Hz geophone
this shows the labelled P and S wave arrivals followed by the very large amplitude T-phase wave arrival at around 07:22 UT
I have shared a number of posts showing recordings of T-phase events over recent years
but this one, to coin a phrase, blows all of them out of the water"
As a reminder and also info to new comers to my posts
The T-phase waves are ones that leave the seafloor at a point roughly above the quake focus and
then travel through a deep sea path till, as in this case, they hit the continental shelf offshore of the east coast of Australia and then travel the last ~ 15 km through the ground to my recording equipment.
The T waves travel much slower than the P and S waves and hence the considerable delay in their arrival, in this case, some 18 minutes after the P wave arrival.
Regards
Dave
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