The Aran Islands just off the coast of Ireland left geologists puzzled for a while now. On top of this cliff huge boulders are found. Up to now the only explanation for waves energetic enough to transport these rocks would be a tsunami. Unfortunately, at least for the explanation, no tsunami happened there since 1755. Now […]

# Category Archives: Earth Science

# The subjective science of seismic interpretation

The final step in the work with seismic data is seismic interpretation. In a scientific field called geophysics, interpretation sounds highly subjective; Very different from the usual statistics, ray and wave phenomenae. This can’t be right, right? I’d love to say it’s very clear and seismic data reveals a perfect image of the subsurface. But […]

# Moeraki Boulders, New Zealand

There are a couple of places in this world, I really would like to see. A friend just added the Moeraki Boulders to this list, posting it to facebook. These are spherical boulders off the coast of New Zealand of unusual size. My first guess, would be dinosaur eggs (wouldn’t that be cool?). The actual explanation […]

# New on StackExchange: Temporal Resolution of Seismic data

Radius of the Fresnel zone is given by [math]Rf=(v/2)(t_0/f_\mathrm{dom})^{1/2}[/math] where v: velocity of layer [math]t_0[/math]: two way travel time [math]f_\mathrm{dom}[/math] :dominant frequency in the spectrum This shows that high frequencies give better resolution than lower frequencies and resolution deteriorates with depth and increasing velocities. However I found some text in “Seismic Data Analysis- Yilmaz” which […]

# To what accuracy and precision do we know the volume of the Earth?

Satellites such as GOCE and GRACE measure the geoid with unprecedented accuracy. Altimeters can determine local surface elevation with millimetre-precision. This makes me wonder: to what precision and accuracy can we measure (or calculate) the volume of the Earth? I’m a lay when it comes to solid Earth, and I find it surprisingly hard to […]

# Dante’s Peak investigated

Dante’s Peak, one of those disaster movies that you either love or hate. Pierce Brosnan saves a dog from Old Smokey tantrum. In the role of a volcanologist we get quite a bit of action such as this scene: Now Rebecca Williams from the University of Hull has taken a closer look at the movie. […]

# Fly over Bardabunga

[youtube http://www.youtube.com/watch?v=lR6p_zuPx9Q]

# Shock Waves on Tavurvur – Volcano Monday

The shock wave on the Tavurvur volcano in Papua New Guinea is really quite impressive!