# M 7.1 Quake Estrn PNG coming in NOW

#### davenn

Gold Member
A decent amplitude on my seismograph

Related Earth Sciences News on Phys.org

#### fresh_42

Mentor
2018 Award
Potsdam has 7.0 in 133 km depth. Sounds deep.

#### davenn

Gold Member
Potsdam has 7.0 in 133 km depth. Sounds deep.

USGS 127 km .... yeah, a reasonably deep event ...... that means the amplitude on my seismo would have been even bigger had it been "normal (shallow)" depth !!

#### davenn

Gold Member
USGS have now upgradsed it to M 7.2 and that doesn't surprise me considering the amplitude it has.
They are now taking into account the depth

and that seismo mob you commented on, have upgraded it to M7.1

Dave

#### fresh_42

Mentor
2018 Award
I always find it really astonishing how precise those measurements from the other side of the planet are. In such a depth the error margin $130 \pm 3$ is pretty good, and $7.0$ to $7.2$ as well, considering the depth. Looks as if we all live on a giant bell.

#### fresh_42

Mentor
2018 Award
Can such deep quakes be felt at the surface in the sense that we should expect damages?

#### davenn

Gold Member
Can such deep quakes be felt at the surface in the sense that we should expect damages?
up to around 150km and M7++, yes for sure, but not likely to be as bad. It's a little different to a M7+ event that is shallow and say 130km away as the Surface waves, the ones that cause most of the damage, are so very much stronger for a shallow event.

here's a graph from wiki showing the drop off of various period surface waves with depth

Interestingly, it can be seen that 50 second period waves pea just below 100km depth

#### davenn

Gold Member
here's a screenshot of my seismogram

"M 7.1 Quake Estrn PNG coming in NOW"

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