solid earth

Seeing and listening to earthquakes

By Chops

The magnitude 6.5-6.8 earthquake to hit New Zealand near Wellington around a week and a half ago brought earthquakes back into the news. Rather than exploring the way the earth rattles and rolls or some other aspect of the science surrounding earthquakes, I thought it might be a great opportunity to explore earthquakes a bit differently. What I want to show off today are some different visualisations (and I use that term loosely here, as will become apparent) of earthquakes that people might find fascinating.

Image of a seismic trace on a drum seismograph. Photo from

Continue reading “Seeing and listening to earthquakes”

Armageddon x 100000 – Bruce Willis = the LHB

by Mike

The LHB, or the ‘Late Heavy Bombardment’ may be the earliest ‘late’ event you have ever heard of. It happened around 4 billion years before you were late for school, and made our planet a particularly unpleasant place to be.

"i have a geological time named after me... DO YOU!?"
“i have a geological time named after me… DO YOU!?” source:

Geologists have a nice name for the period between the formation of the planet and ~4Ga (geology shorthand for 4 billion years ago); we call it the Hadean. Those of you familiar with Greek mythology, or Disney’s Hercules, will know Hades was the god of the Underworld, the guardian of Hell. It is after hell that this time was named, and rightly so. For the first hundred million years or so the earth is not yet solid, it’s a big ball of mixed up melted rock and metal. Later the planet cools down a bit and things are looking up, until along comes the LHB; three hundred million years of continuous bombardment by meteorites.

Continue reading “Armageddon x 100000 – Bruce Willis = the LHB”

Dynamics of the rotation of the inner core

By Chops

Some research came out of RSES last week regarding the rotation of the inner core, and how it speeds up and slows down. This research, made by Hrvoje Tkalcic and others, has got a little bit of publicity ( and also was published in Nature Geoscience last week. In this post, I want to explore a bit of background on how we know what’s happening deep down inside our planet, how this particular research was performed and finally, what sort of significance this sort of work has.

Cutaway of the earth's interior
(Image from iStockphoto/Baris Simsek)

Continue reading “Dynamics of the rotation of the inner core”

Earthquakes and the formation of gold deposits

By Chops

Last month, a piece of geoscience made it (albeit briefly) into the newspapers: namely, the idea that gold forms within earthquakes. This was widely reported, for example ABC Science picked it up and reported it.

Gold from the St Ives Gold Mine, Western Australia
A small sample of ancient gold from Western Australia. New research indicates this gold probably formed in an earthquake 2.5 billion years ago.

Although this news seems quirky more than anything, it is of importance for finding more resources. Although gold is commonly associated with jewellery, it has an equally important role in electronics: modern computers, to name one thing, owe their abilities to gold. Mobile phones have about 50c to $1 worth of gold contained inside them, too; and hey, there’s a heap of mobile phones around these days!

Continue reading “Earthquakes and the formation of gold deposits”

From the archives: Seismologists can’t predict the future…but they can try!

By Mike (originally posted 22nd May 2012)

I picked up a copy of the New Scientist a couple of days ago to shorten the bus ride to Sydney, and one particular article caught my eye, an interesting piece of recent work by some Japanese geophysicists relating to earthquake prediction. The recent post by Evan about the tragic Italian quake reminds us of a sadly acceptable truth; that even in Europe with its high concentration of science and scientists, we cannot predict earthquakes. We can identify regions in which they are likely (like near tectonic plate boundaries or large fault lines) and we can assess the likelihood of a particular sized event occurring in a given time period (say, I predict one magnitude 7 event will occur in region x over 100 years). However, knowing exactly when and where a quake will occur is still about as accurate as my dart throwing ability after 4 pints of beer, or my pool-playing ability before the same amount (i.e. not very accurate).

Continue reading “From the archives: Seismologists can’t predict the future…but they can try!”

From the archives: What do Chocolates and Diamonds have in common?

by Brendan (originally posted 25th May 2012)

Pelletal Lapilli with a diamond core (Source:

Today I came across an interesting headline – Chocolates and diamonds: Why volcanoes could be a girl’s best friend, seems like an unusual combination to me, so I investigated further. It turns a team from the UK, led by Thomas Gernon have been investigating the formation of pelettal lapilli, which are small pieces of rock surrounded by quenched juvenile magma, or in simple terms a piece of rock coated in lava. These are commonly found within kimberlites, which are the major source of diamonds, with this study focusing on kimberlites in South Africa and Lesotho. Continue reading “From the archives: What do Chocolates and Diamonds have in common?”

From the archives: Big numbers from tiny grains

By Kate Boston (originally posted 21st December 2011)

One of the best things about my PhD project is all the cool machines I get to play with. Today I am running a Sensitive High Resolution Ion Microprobe (SHRIMP).  It is one of the more impressive gadgets I get to use.  And what a gadget!  It is a huge, silver, futuristic, impressive-looking  machine with tangles of tubes and wires connecting this thing-amy to that whats-it.  It has switches with labels like “duoplasmatron” (is it just me or does duoplasmatron sound like a space-age weapon or possibly the precursor to the Flux Capacitor?).

 So what does this awe-inspiring contraption do?  This very big machine takes a very small bit of a mineral (we’re talking a 20-30 micron spot size) and analyses the isotopes in it.  I use this for Th-Pb and U-Pb dating.  And the best bit – I can use it to find out how old different growth zones in the same mineral are. This is pretty excellent because I am interested in the rates at which processes like metamorphism occur.

An Active Volcano in Australia

by Brendan

The other day I found some satellite images from NASA’s Earth Observatory that appear to show current volcanic activity at Mawson Peak on Heard Island, an Australian island in the subantarctic Southern Island. The image below was captured by the Earth Observing 1 satellite, on October 13, and it is thought that an eruption happened about an hours before the image was taken.

Continue reading “An Active Volcano in Australia”

Tools of the Trade: Scanning Electron Microscopy

by Brendan

A Jeol 6400 Scanning Electron Microscope, similar to the one I use at ANU. (Image:

As geologists we love to look at our samples but sometimes the features we want to see are too small to be visible using the naked eye or even high-powered optical microscopes, in that case our next point of call is a scanning electron microscope (SEM). We are fortunate at the ANU to have a dedicated unit that operates (and allows us to use) a wide variety of electron microscopes including a number of different SEMs. These machines (we tend to call all large pieces of analytical equipment machines) are used for two purposes, the first being to obtain high resolution, high magnification images of our samples, in my case typically experimental products or natural mineral grains, and the second being to obtain good quality analyses of the major element composition. Continue reading “Tools of the Trade: Scanning Electron Microscopy”

A simple guide to experimental petrology

Piston Cylinder Apparatus, RSES

by Brendan

If you read my bio, you will see that I list one of my areas of study as experimental petrology, and I’m sure plenty of people wonder what that even means, I know I didn’t really understand what it was when I first arrived at RSES to undertake an honours project doing experimental petrology. So what is it? Firstly, ‘petrology’ is the study of rocks, specifically their origin, composition, structure and distribution. The word itself comes from the Greek ‘petra’ – rock and ‘logos’ –study. The experimental in ‘experimental petrology’ is because we do good old fashioned experiments to understand how the rocks form, varying composition, temperature, pressure and a less well known variable ‘oxygen fugacity’. In this post I will try and explain it simple terms, feel free to ask questions via the comments section. Continue reading “A simple guide to experimental petrology”

The geologists are coming to town!

By Kelly

It is almost as exciting as the circus, perhaps for some it is more exciting than the circus, but in reality it is the 34th International Geological Conference (IGC) and it starts  in Brisbane  on the 5th of August. This leaves you plenty of time to get into, or out of, Brisbane depending on how you feel about geologists. I know I wish I was going as it will showcase work from across the geosciences, provide opportunity to mingle (did someone say post doc?) and there is always a field trip involved. Unfortunately I will be missing out on this one, but I do believe most of the Research School will be there so don’t worry, we’ll hear all about it. And until then I shall live vicariously through their particularly cool Facebook page with its plethora of links, photos, videos and articles.

To visit the official site click here or did I mention they have a great Facebook page? You can find it here.

Men of Rock – The Big Freeze

Glen Roy, Scotland (Source:

By Brendan

Over the last couple of weeks I have been watching the BBC documentary, “Men of Rock” (Part 1, Part 2), which details how some of the key ideas in modern geology were formulated, either by Scotsmen or by other geologists working in Scotland. The third and final episode, “The Big Freeze” focuses on the discovery that ice ages have occurred in the past. Continue reading “Men of Rock – The Big Freeze”

Men of Rock – Moving Mountains

Experiment showing convection using dye. (Source:

By Brendan

Last week I wrote about the first episode in the BBC series, “Men of Rock” which investigated “Deep Time”. This I watched the second episode, “Moving Mountains” which details the progression of idea on the formation of mountains (specifically the Scottish Highlands) from early stages through to the modern theory of plate tectonics. Continue reading “Men of Rock – Moving Mountains”

Seismometers in schools

Natalie Balfour looking rather pleased with her seismometer

By Kelly

In a previous post I took a peek at the career trajectory of Dr Natalie Balfour -seismologist and geosciences educator extraordinaire. Natalie is the coordinator of the “Seismometers in Schools” program, which was launched last week at Melrose High School here in Canberra. This week I’d like to follow up with more on the program itself, and why it is an incredibly effective tool to engage young scientists in the Earth Sciences. An idea that is very much in line with a certain blog I know…

“Most seismology lends itself to high school classrooms, particularly when students are learning about the physics of waves, whether it be sound or light” says Natalie. The idea of placing scientific equipment to measure seismic waves is not new, with successful programs run previously in the U.K, the U.S and in France. Students use data collected from their own seismometers to learn about wave properties such as frequency, wavelength and amplitude. However these seismometers are no toys. Display software produces seismographs allowing students to actually apply the fundamentals of maths and physics to their surrounding (and not so surrounding) environment. With the right filtering, this equipment has been able to pick up earthquakes as far as Chile, and even the recent earthquake in Italy! Continue reading “Seismometers in schools”

Men of Rock – Deep Time

Siccar Point, Scotland – Horizontal red sandstone bedding overlaying vertically bedded greywacke. (Source: Dave Souza at Wikipedia)

by Brendan

Yesterday I came across a documentary about some of the Scottish scientists who were instrumental in the development of geology as the science we now know. Presented by Iain Stewart, a Scottish geology professor, the first episode traces the early work of James Hutton. Hutton was one of the first proponents of deep time, as well as developing theories on plutonism and uniformitarianism. Continue reading “Men of Rock – Deep Time”

Volcanoes may grow faster than previously thought

Quartz Crystal (Source: Wikipedia – JJ Harrison)

by Brendan

New research suggests that some of the largest volcanoes on our planet form significantly faster than previously thought. Researchers from the United States, have been investigating the crystallisation of quartz in the magma body that caused that massive Bishop eruption ~760,00 years ago at Long Valley, California. Previous research had focussed on the radiometric dating of whole rock, glass, zircon and feldspar, which suggested that the magma body evolved slowly over as long as 100,000 years. Continue reading “Volcanoes may grow faster than previously thought”

“Nat”ural Hazard

Map of potential sites for AuSIS instruments (red) and existing sites in ACT (yellow). The location and number of stations per state will change depending on school response and logistical considerations. Source:

By Kelly

Our Research School of Earth Sciences has a plethora of talent, tucked away in the many corridors, labs and lecture theatres. This kind of environment can foster a well-rounded graduate (or blog follower) if you actually take the time to go to the many seminars, or talk with your colleagues (or read the blog). Seismology has made it into the news, and into this blog on a number of occasions recently. So with these things in mind, I set off upstairs and was lucky enough to talk to one of our very promising and inspirational early career researchers about her current work. I say lucky as I thought I was busy, however I look positively sluggish next to Dr Natalie Balfour.

Natalie is a post-doctoral fellow in seismology with the Earth Physics group. Her position is a little different from most as she is not only a researcher – she works on the source mechanisms and rupture models for earthquakes in Indonesia – she is also coordinating the Australian Seismometers in Schools Network. And so, her position is funded through a combination of a joint linkage project with AusAid/ARC, the Australian Governments Overseas Aid Program and the Australian Research Council, and AuScope, an organisation for a national earth science infrastructure program. So how does one end up being a seismologist leading the coordination of national educational programme? Continue reading ““Nat”ural Hazard”

What do Chocolates and Diamonds have in common?

by Brendan

Pelletal Lapilli with a diamond core (Source:

Today I came across an interesting headline – Chocolates and diamonds: Why volcanoes could be a girl’s best friend, seems like an unusual combination to me, so I investigated further. It turns a team from the UK, led by Thomas Gernon have been investigating the formation of pelettal lapilli, which are small pieces of rock surrounded by quenched juvenile magma, or in simple terms a piece of rock coated in lava. These are commonly found within kimberlites, which are the major source of diamonds, with this study focusing on kimberlites in South Africa and Lesotho. Continue reading “What do Chocolates and Diamonds have in common?”

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