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Earthquakes in the laboratory: Part 1 – Paris

By Kathryn Hayward

In 2016, I was fortunate enough to be awarded a 34th IGC Early Career Travel Grant and the RSES Mervyn and Katalin Paterson Travel Fellowship. These awards allowed me travel for an extended period this year to attend conferences and undertake state-of-the-art laboratory experiments at the École Normale Supérieure (ENS) in Paris and the National Institute of Volcanology and Geophysics (INVG) in Rome.

In this article I will talk a little about my experiences at the ENS laboratories in Paris. During my stay I was able to use experimental techniques pioneered by the ENS lab to explore differences in fault processes between earthquakes resulting from increases in shear stress (such as classic mainshock-aftershock events) and those driven by changes in pore fluid pressure (e.g. during an injection driven swarm sequence). Working closely with Professor Alexandre Schubnel and PhD student Jérôme Albury, I was able to undertake six experiments during the four weeks of my visit.

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The École Normale Supérieure laboratories in the Latin Quarter of Paris.

The aim of my research is to use experiments undertaken at pressure and temperature conditions comparable to those found deep in the crust to learn about the strength and behaviour of faults. I am interested in understanding the processes that occur during the first seconds of fault slip as this is central to understanding whether a fault rupture grows to become a large, damaging earthquake, or whether strain is accommodated as a small, possibly non-seismic event. During the first seconds of slip, the extreme forces acting on fault contacts, or asperities, result in heat generation, formation of damage and changes in the physical properties of a fault surface. As slip proceeds, these processes can result in an evolution of fault strength through a process referred to as ‘dynamic weakening’.

A key aspect of my current research, and the reason for my trip to Paris, was to look at role that fluids play in affecting the behaviour of faults during the initial stages of slip. Fault zones are recognised as fluid conduits within the crust and large-scale injection experiments (such as in Basel, Switzerland) have shown a direct correlation between fluid pressure and rates of seismicity. This has important implications for the development of hydraulic fracture technologies such as enhanced gas recovery, geothermal energy extraction and geo-sequestration. However, little is currently known about how pore fluids modify fault strength and asperity behaviour during rupture and how this could facilitate or impede rupture propagation.

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Standing in front of the deformation apparatus with collaborators Alexandre Schubnel and Jérôme Albury

The lab at ENS has pioneered the use of two different types of sensors mounted on the sample as way of measuring deformation prior to and during the onset of slip. The first technique involves the detection and measurement of Acoustic Emissions (AEs). AEs are generated when structural changes, such as a brittle fracture, form a local source of elastic waves. Just like an earthquake only much, much smaller, the elastic waves generate tiny displacements on the sample surface that are detected using piezoelectric sensors. By looking at the rate and source of emissions we can gain insights into where the larger-scale macroscopic labquakes nucleate. The second type of measurement involves the use of strain gauges, which we glue adjacent to the slip surface. These sensors are important for recording the coseismic release of stored elastic energy. If we record multiple strain gauges synchronously we can use the time difference between the onset of energy release to determine the speed at which the labquake rupture propagates.

During my visit I performed six experiments on Fontainebleau sandstone, a pure quartz sandstone that is highly prized for use by experimental rock physicists owing to its purity, lack of preexisting deformation and beautiful pore structure. It just so happens that my piece of Fontainebleau sandstone was salvaged from the Palace of Versailles. It did seem rather surreal to be deforming part of one of France’s greatest icons!

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Coring a pavement stone from the Palace of Versailles.

Preparation for each experiment took the better part of a week. The samples had to be cored and ground, and the sixteen sensors carefully glued into position. However, all the fiddly preparation was worth it when the experiments worked and we were able to produce some exciting results. During the experiments we recorded thousands of little ‘fore-shock’ AEs in the lead up to the main macroscopic slip events.

Now, in a similar manner to the way seismologists pick events from different seismograms, we must pick the events from our 8 acoustic emission sensors. If we can correlate AE events between the different sensors we can calculate travel times and estimate the hypocenter locations. This work will take months to complete but we hope that it will provide us with new insights into how fluids alter the dynamics of rupture on a fault. Now that I am back in Australia, I am also using high-resolution electron microscopy imaging to look at physical changes that have occurred on the fault surfaces during slip in an attempt to correlate microstructural and behavioral evolution.

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The sample with all its sensors attached following a successful experiment. Here at ANU we use argon as a confining medium – in Paris they use oil and it takes some getting used to!

A month in Paris was a wonderful experience. Yes, I sampled many fine desserts from numerous patisseries, but I also had the opportunity to develop new skills and learn new experimental techniques in a hands-on way. No doubt, what I have learnt will shape my future endeavors and I would like to extend my sincere thanks to the Australian Geoscience Council, the Australian Academy of Science, the Research School of Earth Sciences and Mervyn and Katalin Paterson for the provision and the award of the travel grants that made this trip possible.

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One of the indulgent little delicacies that Paris had to offer…

Rig 1’s 50th Birthday Party: Celebrating 50 years rock deformation research at RSES

By Kathryn Hayward

On 16 November next month, RSES will be celebrating a significant milestone – the 50th Birthday of our first high temperature high pressure rock deformation apparatus, developed and built in-house by Professor Mervyn Paterson. These apparatus marked a major global advance in the ability to measure and understand the strength, rheology and behaviour of earth materials at pressures and temperatures equivalent to depths of 20km in the crust. Even today, 50 years on, these gas medium apparatus remain relevant, achieving unsurpassed mechanical accuracy at high pressure-temperature conditions.

Photo 1
A living legend: Mervyn Paterson at his 90th birthday celebrations. Mervyn’s association with RSES spans more than 50 years from 1953-2017. During his time at the School Mervyn has achieved much in the field of rock deformation but he has also given the School a great deal. Many students have benefited from the gift of travel through the Mervyn and Katalin Paterson Travel Fellowship.

Many of us have seen Professor Mervyn Paterson, now aged 92, at tea and around the School – but who was he and what did he do that was so significant? Mervyn spent his career working as geophysicist and instrument developer, specializing in rock deformation. He was born into a farming family in South Australia in 1925 and attended the Adelaide Technical High School. In 1943 he completed his undergraduate studies in metallurgy at the University of Adelaide. Mervyn began his career at the CSIR Division of Aeronautics working on the physics of metal fatigue in a position that would now be called a ‘materials scientist’. He received a PhD from the University of Cambridge in the UK on x-ray diffraction effects of deformation in metals, and pursued postdoctoral studies in Chicago in the USA.

In 1951 Mervyn returned to Australia to work at the newly-named CSIRO, but was soon approached by Professor John Jaeger and appointed to pursue research in the field of experimental rock deformation within the Department of Geophysics at the Australian National University. Commencing in 1953, Mervyn remained as a researcher at the subsequently formed Research School of Earth Sciences until his retirement in 1990. During this time he developed the instruments that we have today in the High Pressure Rock Physics Lab and undertook seminal research into the strength and behavior of many crustal materials including work on quartz, calcite and olivine. Following ‘retirement’ Mervyn proceeded to have a second career as the chairman of Paterson Instruments Pty Ltd, a company which oversaw the development of all the ‘commercial’ Paterson apparatus that are the pride of many rock deformation labs around the world. Not one to take retirement too easily, Mervyn published his last book at the age of 88, titled ‘Materials Science for Structural Geology’.

Photo 2
The master at work: Mervyn Paterson with the control console of Rig 1 in 1983. Due to the high gas pressures contained within the pressure vessel during experiments, for safety reasons the apparatus must be isolated. The machine can be operated and the experiment run entirely from outside the high pressure bay.

The Rock Physics lab at RSES is in the fortunate position of being the envy of many experimental rock physicists, with an unprecedented three (3) high temperature, high pressure gas apparatus. These include two deformation apparatus and the attenuation apparatus, which is used to measure seismic properties of rocks at crustal to mantle conditions. When thinking about national infrastructure and capacity, it is worth highlighting that we are the only rock physics lab with ability to explore high pressure, high temperature, fluid saturated conditions in the Southern Hemisphere.

But what makes these machines so special? Central to the operation of these machines is the pressure vessel – a big cylinder of steel that can be pressurized. We use argon gas as the medium that we pressurize to between 3000 to 5000 atmospheres (300-500 MPa or, for our petrologist friends, 3-5 kbar). Inside the pressure vessel we have a furnace that raises the temperature as high as 1300 °C. A load or force is applied to the sample, making it deform either plastically or by brittle failure, forming miniature ‘labquakes’. During deformation, the applied forces are measured inside the pressure vessel, giving unrivaled accuracy of the mechanical data. In particular, internal measurement removes effects such as the frictional contribution of the high pressure seals. Although the design is seemingly quite simple, Mervyn’s machines remain the only gas-medium apparatus that can operate in the given P-T space. As a number of other researchers have discovered to their dismay when trying to build an equivalent, the devil is in the detail!

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50 years young: The pressure vessel and loading frame of Rig 1. You can also see the gas and pore fluid intensification systems on the right of the photo.

Rig 1 is technically not the first pressure vessel of its kind at ANU, but rather it is the oldest surviving one. In the early days of rock deformation, people did not fully understand the effects of corrosion, hydrogen embrittlement and pressure cycling on strength of the apparatus. It was also during the heady days of pumping gas to 1 GPa (10 kbar) and on one fine morning in 1964 the first pressure vessel on Rig 1 exploded…

Thankfully Mervyn had designed and built the lab planning for the worst. The machine was contained within a bunker with 30 cm thick concrete walls. No one was injured and there was surprisingly little damage (except to the pressure vessel). The shards of the vessel can still be found in the lab and serve as a reminder to all users of what can happen.

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The founding fathers: our three professors in the Rock Physics lab in 1988. Left to right: Mervyn Paterson, Ian Jackson and Stephen Cox

You might be thinking that after 50 years of service Rig 1 might be due for retirement. Nothing could be further from the truth and it remains as relevant today as when it was built. One of Rig 1’s main assets is versatility: over the past decades it has been a platform for numerous research ventures ranging from meticulously defining rheological properties of earth materials to my current research interests exploring the first stages of earthquake slip.

In 2015 an innovative partnership was established with physicists from the Department of Quantum Physics to build a unique measurement system to capture, for the first time, the mechanical behavior of tiny earthquakes produced in the lab. We combined Nobel Prize-winning technology used for the detection of gravity waves, with the unique pressure and temperature environment provided by Rig 1. With this capability we are now begining to unravel the secrets of earthquake initiation at realistic mid crustal-conditions – one of the great unresolved enigmas of geophysics. In 2016 this endeavor captured the attention of the Major Equipment Committee and the project was awarded a grant that has allowed continued development, and culminated in an instrument that is truly globally unique. The up-coming Birthday Party is an opportunity to celebrate not only the wonderful and rich history of this machine but also to showcase its exciting future.

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New capabilities: the optical interferometer designed and built in partnership with the Department of Quantum Physics (RSPE). Left to right: Bram Slagmolen, Kathryn Hayward, Stephen Cox and Perry Forsyth.

Former lab users and guests will be coming from around the world to mark the occasion of the 50th anniversary of the first use Rig 1. On 16 November we will be having a series of seminars with talks given by our visitors and current lab users. The day will start with tours of the High Pressure Rock Physics Laboratory – so please join in and visit one of RSES’s hidden gems! Following the tours there will be a school morning tea. Details of the seminar program will be posted shortly and everyone is very welcome to attend.

References:  Lambeck, K., Paterson, M. 2006 ‘Professor Mervyn Paterson, geophysicist’ Interviews with Australian Scientists, Australian Academy of Science.

10 ways to keep sane during your PhD

The following is a list collated by a number of PhD students almost at the end of their program. This is usually the most stressful time and these are the best ways we’ve found to keep sane.

 

1. Keep your hobbies


Don’t give up on the things you love. Make time for them.

 

2. Go to tea!


There is tea time in the J1 seminar room every day at 10:30-11:00am and its a great opportunity to decompress and chat with colleges

3. Remember to exercise


Exercise improves your mood and can clear your mind.

 

4. Walking and talking


If you’re starting to stress out, walking and chatting with a friend is a great way to vent all your frustration and pry you away from your desk.

 

5. #SanitityInNumbers


There are many students in the school and the rest of ANU that are going through the same things you are. There are many opportunities to “shut up and write” including; shut up and write nights, shut up and write days, and if you need an extreme kick up the butt, thesis boot camp. You can also start your own writing group/working group to get some productive peer pressure. Remember #sanityinnumbers

 

6. Achieve some small tasks


If you break everything up into to tiny task you can bring a little joy into your project by ticking off small tasks. These include life tasks if you really need a break from the PhD

 

7. feng shui your office and home


If you organise the space around you, your thoughts will follow (probably)

 

8. Make plans that you can look forward to


Make some plans. A nice weekend. A night off. Dinner with a friend. Look forward to these things and enjoy them when you’re there!

 

 9. Learn to switch off

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If you can switch off, it will do your brain wonders

 

10. Seek help when you need it

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If you’re really struggling and don’t know how to make yourself feel better, make sure you seek help. There is a counseling center at the university with same day appointments.

 

Palaeoclimate in a Medieval city

By Tiah Penny

For three weeks of July I go to say “arrivederci” to the Canberra winter, as I travelled to Italy to attend the 14th Urbino Summer School in Palaeoclimateology (USSP). The summer school was taught by some of the leading scientists in the field of palaeoclimate, and attended by over 70 palaeoclimate nerds – I mean HDR students – from around the world. Continue reading “Palaeoclimate in a Medieval city”

#GetSoMe

By Shannon McConachie

When I started my PhD last year, I knew there were three areas I would have the next few years to refine my skills in; research, teaching, and outreach. Research and teaching I knew where to go, but outreach? I hadn’t the faintest clue where to start looking and was, frankly, mildly terrified of the concept.

Then came the email. Inger Mewburn, The Thesis Whisperer, would be running a new course on social media for researchers. After some prodding from my office mate I signed on up and have not regretted it.

Continue reading “#GetSoMe”

Photos From Our RSES Adventures. Vol. 6.

This is the last of our photography competition photos here on the blog. If you want to look at more or see what else we get up to at RSES, check out our Instagram!

Continue reading “Photos From Our RSES Adventures. Vol. 6.”

Photos From Our RSES Adventures. Vol. 5.

This week we have some shots from field trips undertaken by PhD, Masters and Undergrad students at RSES! Enjoy.

Continue reading “Photos From Our RSES Adventures. Vol. 5.”

Photos From Our RSES Adventures. Vol. 4.

This week’s photo installment was going to be the People’s Choice winners! But, one of the winners was featured in volume 1 (A foraminifera catching and beginning to eat a copepod by Dr. Oscar Branson), so this installment instead contains the stories of the two other winner of the People’s Choice prizes, and then an writers choice photo! Enjoy.

People’s Choice Award for ‘Where We Go’

– Dr Jonathan Pownall (ARC DECRA Fellow in Structure Tectonics)

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In November last year, I travelled to Arthur’s Pass National Park on New Zealand’s South Island.  Walking from Arthur’s Pass Village—New Zealand’s highest settlement—I climbed for a few hours up Avalanche Peak, just above the snow line, where I was greeted by a number of Keas, the world’s only ‘Alpine’ parrots.  I took a few photos, surprised by how close I was able to approach (I had only a wide-angle lens).  And by how enthusiastically they were trying to destroy my rucksack, which I left on a nearby rock.  I’d like to say that some level of skill was behind this photograph, but the truth is that it was just a lucky shot.  A spilt second before I took the photo of the Kea on the right, it was scared by another Kea landing to the photo’s left, and burst into flight.  The result: an amazing glimpse at the Keas’ fiery-orange outstretched wings amid the spectacular snow-capped Southern Alps.

Continue reading “Photos From Our RSES Adventures. Vol. 4.”

Photos From Our RSES Adventures. Vol. 3.

This week we are sharing a bunch of interesting photos of places and samples from around Australia and the world. Enjoy.

Can You Do This? Mulga, Central Australia

– Associate Professor Hrvoje Tkalčić (Seismology and Mathematical Geophysics)

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This camel photo was taken when Armando Arcidiaco (our technical officer) and myself were in the field to retrieve 6 ANU seismic instruments that we installed to monitor the aftershock activity from a large (magnitude 6.1) earthquake that shook central Australia on May 21, 2016. The shot was taken while Armando was driving and I was in a good position to observe the beautiful landscape and nature of Mulga National Park, about 100 km southwest of Uluru. There was a wild excitement in the animals due to an unusually large amount of water (a consequence of La Nina) and thriving vegetation in usually desolate areas.

Continue reading “Photos From Our RSES Adventures. Vol. 3.”

Photos From Our RSES Adventures. Vol. 2.

This week we bring you the Highly Commended images from our inaugural Photography Competition. Well the first three images are, and the last image is an ‘authors pick’! Enjoy.

 

What We Study

Chert – Jeremy Mole (Undergrad Earth and Marine Science Student)

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I took this photo at an outcrop on Melville Point, NSW during the EMSC1008 south coast field trip run by Dr. Andrew Berry in September 2016. It is a picture of a series of cherts, which are fine grained organic sedimentary rocks formed by a process called diagenesis, where siliceous skeletons of marine plankton are dissolved, and the silica re-precipitated from the resulting solution. The chert can be of many colours such as brown, grey, yellow, red and white as seen in the photo. Also featuring in the photo are some well-defined fold structures.

Although it was a cloudy, rainy, wet day, the colours were still so vibrant that I took a couple of photos. Nothing fancy, just low aperture

Continue reading “Photos From Our RSES Adventures. Vol. 2.”

Photos From Our RSES Adventures. Vol.1

As part of our annual Student Conference, this year we held our first ever RSES Photography Competition! Over the coming months we are going to be sharing with you some of these photos, and the stories and science behind them.

This week we start on a high with the winning images from our three categories; Where We Go, Who We Are and What We Study, as well as the overall winner. Enjoy!

Where We Go

Milky Way + Tent – Dr. Jonathan Pownall (ARC DECRA Fellow)

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The photo was taken in August 2014 during a trip to Ladakh in the Indian Himalaya with Dr. Marnie Forster.  We were undertaking geological mapping and structural analysis of shear zones related to the exhumation of UHP coesite-bearing eclogites.  One night, camping by Tso Kar lake (4500 m), I opened my tent, and the sky was amazingly clear, and the Milky Way looked pretty special.  The lamp was still on in the kitchen tent… so I balanced my camera on a rock and took a long exposure photo.

Continue reading “Photos From Our RSES Adventures. Vol.1”

Why we should March for Science

By Ali and Jess

Five reasons YOU should March for Science TOMORROW:

  1. You believe that government decisions should be guided by facts and evidence. March for Informed Public Policy!
  2. To say no to restrictions being placed on scientists communicating their research, as we are currently seeing in the U.S. Show your support for Open Communication of Knowledge!
  3. For Stable Science Investment, for security in our future jobs!
  4. For a science informed future and a well-informed community. We need kids to learn and love science, they are the future! We need Universal STEM Literacy!
  5. Finally, science is our tool to solve some of the world’s most challenging problems; it is worth marching for!

Continue reading “Why we should March for Science”

Tools of the trade: Michael Anenburg

This is the first post in a series where students will have the chance to write about their favourite tech tools to get the job done. This includes software, hardware, mobile apps, etc.

By Michael

I am an experimental petrologist, high temperature geochemist and a general geologist. This is what I use.

Continue reading “Tools of the trade: Michael Anenburg”

PhD by haiku, vol. 4

Compiled by Patrick, Patrick and Louise.

The fourth and potentially final installation of our longest running series.

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Buried in a grave
Sea of torrid rock and heat
Spawns a seed so deep
— Jess, experimental petrology

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Flash rock plummets scorched earth
Oasis of questions
Frostily protected
— Liane, isotope geochemistry

Continue reading “PhD by haiku, vol. 4”

PhD by haiku, vol. 3

Compiled by Patrick, Patrick and Louise.

A continuation of a continuation of our PhD haiku’s.

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Such a mystery zircon
So obsessed with you
Let me know you more
— Bei, isotope geochemistry

slide15

The sea-floor goes deep
Water is lost on the way
Looking for witness
— Laure, isotope geochemistry

Continue reading “PhD by haiku, vol. 3”

Virtual Reality is the Future

By Michael

Several of us recently visited the VR exhibition at the National Museum Australia. You sit in their theatre and they give you an Oculus Rift with which you see two short films. Here are two videos to give you an idea of what it is:

Continue reading “Virtual Reality is the Future”

PhD by haiku, vol. 2

Compiled by Patrick, Patrick and Louise.

 

A continuation from last weeks blog post.

Suzette
Nitrogen, carbon
Noble gases and so on
Chemistry is key
— Suzette, isotope geochemistry

Louise

Two minerals paired
trap ancient information
of how they were made
— Louise, experimental petrology

Continue reading “PhD by haiku, vol. 2”

PhD by haiku, vol. I

Compiled by Patrick, Patrick and Louise

We asked members of the student body to summarise their research in the form of a haiku. Here is what they came up with…

tim-j

Dear sweet mantle plume
I really hope you exist
So much wasted time
— Tim, geodynamics

hannah

Where did people live?
Isotopes in teeth can help,
to stalk ancient folk
— Hannah, isotope geochemistry

Continue reading “PhD by haiku, vol. I”

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