- #1
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M 7.1 Quake Estrn PNG coming in NOW
- Thread starter davenn
- Start date
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SUMMARY
The recent seismic event near Potsdam has been upgraded to a magnitude of 7.2, with a depth of 133 km, indicating a significant amplitude on seismographs. The USGS and other seismology sources confirm the depth's impact on the amplitude readings, suggesting that had the quake been shallower, the amplitude would have been even greater. Discussions highlight that while deep earthquakes can be felt at the surface, they typically cause less damage compared to shallow events of similar magnitude due to weaker surface waves.
PREREQUISITES- Understanding of seismic wave types and their impact on surface damage
- Familiarity with seismograph readings and amplitude measurement
- Knowledge of earthquake magnitude scales, particularly the Richter scale
- Basic concepts of earthquake depth and its correlation with surface effects
- Research the relationship between earthquake depth and surface wave amplitude
- Study the differences in damage potential between shallow and deep earthquakes
- Learn about the methodologies used by USGS for earthquake magnitude upgrades
- Examine seismic data interpretation techniques using seismograms
Seismologists, earthquake researchers, disaster response planners, and anyone interested in understanding the implications of deep seismic events on surface conditions.
- #2
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Potsdam has 7.0 in 133 km depth. Sounds deep.
http://geofon.gfz-potsdam.de/eqinfo/seismon/globmon.php
http://geofon.gfz-potsdam.de/eqinfo/seismon/globmon.php
- #3
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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 !fresh_42 said:
- #4
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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
http://geofon.gfz-potsdam.de/eqinfo/seismon/globmon.php
Dave
They are now taking into account the depth
http://geofon.gfz-potsdam.de/eqinfo/seismon/globmon.php
Dave
- #5
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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.
- #6
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Can such deep quakes be felt at the surface in the sense that we should expect damages?davenn said:
- #7
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fresh_42 said:
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
- #8
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here's a screenshot of my seismogram
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