# Hooke's oolite

52 Things You Should Know About Rock Physics came out last week. For the first, and possibly the last, time a Fellow of the Royal Society — the most exclusive science club in the UK — drew the picture on the cover. The 353-year-old drawing was made by none other than Robert Hooke

The title page from Micrographia, and part of the dedication to Charles II. You can browse the entire book at archive.org.

The drawing, or rather the engraving that was made from it, appears on page 92 of Micrographia, Hooke's groundbreaking 1665 work on microscopy. In between discovering and publishing his eponymous law of elasticity (which Evan wrote about in connection with Lamé's $$\lambda$$), he drew and wrote about his observations of a huge range of natural specimens under the microscope. It was the first time anyone had recorded such things, and it was years before its accuracy and detail were surpassed. The book established the science of microscopy, and also coined the word cell, in its biological context.

Sadly, the original drawing, along with every other drawing but one from the volume, was lost in the Great Fire of London, 350 years ago almost to the day.

### Ketton stone

The drawing on the cover of the new book is of the fractured surface of Ketton stone, a Middle Jurassic oolite from central England. Hooke's own description of the rock, which he mistakenly called Kettering Stone, is rather wonderful:

I wonder if anyone else has ever described oolite as looking like the ovary of a herring?

These thoughtful descriptions, revealing a profundly learned scientist, hint at why Hooke has been called 'England's Leonardo'. It seems likely that he came by the stone via his interest in architecture, and especially through his friendsip with Christopher Wren. By 1663, when it's likely Hooke made his observations, Wren had used the stone in the façades of several Cambridge colleges, including the chapels of Pembroke and Emmanuel, and the Wren Library at Trinity (shown here). Masons call porous, isotropic rock like Ketton stone 'freestone', because they can carve it freely to make ornate designs. Rock physics in action!

You can read more about Hooke's oolite, and the geological significance of his observations, in an excellent short paper by material scientist Derek Hull (1997). It includes these images of Ketton stone, for comparison with Hooke's drawing:

Reflected light photomicrograph (left) and backscatter scanning electron microscope image (right) of Ketton Stone. Adapted from figures 2 and 3 of Hull (1997). Images are © Royal Society and used in accordance with their terms.

I love that this book, which is mostly about the elastic behaviour of rocks, bears an illustration by the man that first described elasticity. Better still, the illustration is of a fractured rock — making it the perfect preface.

References

Hall, M & E Bianco (eds.) (2016). 52 Things You Should Know About Rock Physics. Nova Scotia: Agile Libre, 134 pp.

Hooke, R (1665). Micrographia: or some Physiological Descriptions of Minute Bodies made by Magnifying Glasses, pp. 93–100. The Royal Society, London, 1665.

Hull, D (1997). Robert Hooke: A fractographic study of Kettering-stone. Notes and Records of the Royal Society of London 51, p 45-55. DOI: 10.1098/rsnr.1997.0005.

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### Matt Hall

Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning.

# 52 Things... Rock Physics

There's a new book in the 52 Things family!

52 Things You Should Know About Rock Physics is out today, and available for purchase at Amazon.com. It will appear in their European stores in the next day or two, and in Canada... well, soon. If you can't wait for that, you can buy the book immediately direct from the printer by following this link.

The book mines the same vein as the previous volumes. In some ways, it's a volume 2 of the original 52 Things... Geophysics book, just a little bit more quantitative. It features a few of the same authors — Sven Treitel, Brian Russell, Rachel Newrick, Per Avseth, and Rob Simm — but most of the 46 authors are new to the project. Here are some of the first-timers' essays:

• Arthur Cheng, How to catch a shear wave.
• Peter Duncan, Mapping fractures.
• Paul Johnson, The astonishing case of non-linear elasticity.
• Chris Liner, Negative Q.
• Chris Skelt, Five questions to ask the petrophysicist.

It's our best collection of essays yet. We're very proud of the authors and the collection they've created. It stretches from childhood stories to linear algebra, and from the microscope to seismic data. There's no technical book like it.

### Matt Hall

Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning.

The linkfest has come early this month, to accommodate the blogging blitz that always accompanies the SEG Annual Meeting. If you're looking forward to hearing all about it, you can make sure you don't miss a thing by getting our posts in your email inbox. Guaranteed no spam, only bacn. If you're reading this on the website, just use the box on the right →

### Open geoscience goodness

I've been alerted to a few new things in the open geoscience category in the last few days:

• Dave Hale released his cool-looking fault detection code
• Wayne Mogg released some OpendTect plugins for AVO, filtering, and time-frequency decomposition
• Joel Gehman and others at U of A and McGill have built WellWiki, a wiki... for wells!
• Jon Claerbout, Stanford legend, has released his latest book with Sergey Formel, Austin legend: Geophysical Image Estimation by Example. As you'd expect, it's brilliant, and better still: the code is available. Amazing resource.

And there's one more resource I will mention, but it's not free as in speech, only free as in beerPetroacoustics: A Tool for Applied Seismics, by Patrick Rasolofosaon and Bernard Zinszner. So it's nice because you can read it, but not that useful because the terms of use are quite stringent. Hat tip to Chris Liner.

So what's the diff if things are truly open or not? Well, here's an example of the good things that happen with open science: near-real-time post-publication peer review and rapid research: How massive was Dreadnoughtus?

### Technology and geoscience

Open data sharing has great potential in earthquake sensing, as there are many more people with smartphones than there are seismometers. The USGS shake map (right) is of course completely perceptual, but builds in real time. And Jawbone, makers of the UP activity tracker, were able to sense sleep interruption (in their proprietary data): the first passive human-digital sensors?

We love all things at the intersection of the web and computation... so Wolfram Alpha's new "Tweet a program" bot is pretty cool. I asked it:

GeoListPlot[GeoEntities[=[Atlantic Ocean], "Volcano"]]

And I got back a map!

This might be the coolest piece of image processing I've ever seen. Recovering sound from silent video images:

Actually, these time-frequency decompositions [PDF] of frack jobs are just as cool (Tary et al., 2014, Journal of Geophysical Research: Solid Earth 119 (2), 1295-1315). These deserve a post of their own some time.

It turns out we can recover signals from all sorts of unexpected places. There were hardly any seismic sensors around when Krakatoa exploded in 1883. But there were plenty of barometers, and those recorded the pressure wave as it circled the earth — four times! Here's an animation from the event.

It's hard to keep up with all the footage from volcanic eruptions lately. But this one has an acoustic angle: watch for the shockwave and the resulting spontaneous condensation in the air. Nonlinear waves are fascinating because the wave equation and other things we take for granted, like the superposition principle and the speed of sound, no longer apply.

### Discussion and collaboration

Our community has a way to go before we ask questions and help each other as readily as, say, programmers do, but there's enough activity out there to give hope. My recent posts (one and two) about data (mis)management sparked a great discussion both here on the blog and on LinkedIn. There was also some epic discussion — well, an argument — about the Lusi post, as it transpired that the story was more complicated that I originally suggested (it always is!). Anyway, it's the first debate I've seen on the web about a sonic log. And there continues to be promising engagement on the Earth Science Stack Exchange. It needs more applied science questions, and really just more people. Maybe you have a question to ask...?

### Géophysiciens avec des ordinateurs

Don't forget there's the hackathon next weekend! If you're in Denver, free come along and soak up the geeky rays. If you're around on the afternoon of Sunday 26 October, then drop by for the demos and prizes, and a local brew, at about 4 pm. It's all happening at Thrive, 1835 Blake Street, a few blocks north of the convention centre. We'll all be heading to the SEG Icebreaker right afterwards. It's free, and the doors will be open.

Comment

### Matt Hall

Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning.

# Whither technical books?

Leafing through our pile of new books on seismic analysis got me thinking about technical books and the future of technical publishing. In particular:

• Why are these books so expensive?
• When will we start to see reproducibility?
• Does all this stuff just belong on the web?

### Why so expensive?

Should technical books really cost several times what ordinary books cost? Professors often ask us for discounts for modelr, our $9/mo seismic modeling tool. Students pay 10% of what pros pay in our geocomputing course. Yet academic books cost three times what consumer books cost. I know it's a volume game — but you're not going to sell many books at$100 a go! And unlike consumer books, technical authors usually don't make any money — a star writer may score 6% of net sales... once 500 books have been sold (see Handbook for Academic Authors).

### Where's the reproducibility?

Compared to the amazing level of reproducibility we saw at SciPy — where the code to reproduce virtually every tutorial, talk, and poster was downloadable — books are still rather black box. For example, the figures are often drafted, not generated. A notable (but incomplete) exception is Chris Liner's fantastic (but ridiculously expensive) volume, Elements of 3D Seismology, in which most of the figures seem to have been generated by Mathematica. The crucial final step is to share the code that generated them, and he's exploring this in recent blog posts (e.g. right).

I can think of three examples of more reproducible geophysics in print:

1. Gary Mavko has shared a lot of MATLAB code associated with Quantitative Seismic Interpretation and The Rock Physics Handbook. The code to reproduce the figures is not provided, and MATLAB is not really open, but it's a start.
2. William Ashcroft's excellent book, A Petroleum Geologist's Guide to Seismic Reflection contains (proprietary, Windows only) code on a CD, so you could in theory make some of the figures yourself. But it wouldn't be easy.
3. The series of tutorials I'm coordinating for The Leading Edge has, so far, includes all code to reproduce figures, exclusively written in open languages and using open or synthetic data. Kudos to SEG!

### Will the web win?

None of this comes close to Sergey Fomel's brand of fully reproducible geophysics. He is a true pioneer in this space, up there with Jon Claerbout. (You should definitely read his blog!). One thing he's been experimenting with is 'live' reproducible documents in the cloud. If we don't see an easy way to publish live, interactive notebooks in the cloud this year, we'll see them next year for sure.

So imagine being able to read a technical document, a textbook say, with all the usual features you get online — links, hover-over, clickable images, etc. But then add the ability to not only see the code that produced each figure, but to edit and re-run that code. Or add slider widgets for parameters — "What happens to the gather if if I change Poisson's ratio?" Now, since you're on the web, you can share your modification with your colleagues, or the world.

Now that's a book I'd be glad to pay double for.

### Some questions for you

We'd love to know what you think of technical books. Leave a comment below, or get in touch

• Do you purchase technical books regularly? What prompts you to buy a book?
• What book keeps getting pulled off your shelf, and which ones collect dust?
• What's missing from the current offerings? Workflows, regional studies, atlases,...?
• Would you rather just consume everything online? Do you care about reproducibility?

### 400 posts

The last post was our 400th on this blog. At an average of 500 words, that's about 200,000 words since we started at the end of 2010. Enough for a decent-sized novel, but slightly less likely to win a Pulitzer. In that time, according to Google, almost exactly 100,000 individuals have stopped by agilegeoscience.com — most of them lots of times — thank you readers for keeping us going! The most popular posts: Shale vs tight, Rock physics cheatsheet, and Well tie workflow. We hope you enjoy reading at least half as much as we enjoy writing.

### Matt Hall

Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning.

# Six books about seismic analysis

Last year, I did a round-up of six books about seismic interpretation. A raft of new geophysics books recently, mostly from Cambridge, prompts this look at six volumes on seismic analysis — the more quantitative side of interpretation. We seem to be a bit hopeless at full-blown book reviews, and I certainly haven't read all of these books from cover to cover, but I thought I could at least mention them, and give you my first impressions.

Observation: none of these volumes mention compressive sensing, borehole seismic, microseismic, tight gas, or source rock plays. So I guess we can look forward to another batch in a year or two, when Cambridge realizes that people will probably buy anything with 3 or more of those words in the title. Even at $75 a go. ### Quantitative Seismic Interpretation Per Avseth, Tapan Mukerji and Gary Mavko (2005). Cambridge University Press, 408 pages, ISBN 978-0-521-15135-1. List price USD 91,$81.90 at Amazon.com, £45.79 at Amazon.co.uk

You have this book, right?

Every seismic interpreter that's thinking about rock properties, AVO, inversion, or anything beyond pure basin-scale geological interpretation needs this book. And the MATLAB scripts.

Gary Mavko, Tapan Mukerji & Jack Dvorkin (2009). Cambridge University Press, 511 pages, ISBN 978-0-521-19910-0. List price USD 100, $92.41 at Amazon.com, £40.50 at Amazon.co.uk If QSI is the book for quantitative interpreters, this is the book for people helping those interpreters. It's the Aki & Richards of rock physics. So if you like sums, and QSI left you feeling unsatisifed, buy this too. It also has lots of MATLAB scripts. ### Seismic Reflections of Rock Properties Jack Dvorkin, Mario Gutierrez & Dario Grana (2014). Cambridge University Press, 365 pages, ISBN 978-0-521-89919-2. List price USD 75,$67.50 at Amazon.com, £40.50 at Amazon.co.uk

This book seems to be a companion to The Rock Physics Handbook. It feels quite academic, though it doesn't contain too much maths. Instead, it's more like a systematic catalog of log models — exploring the full range of seismic responses to rock properies.

Hua-Wei Zhou (2014). Cambridge University Press, 496 pages, ISBN 978-0-521-19910-0. List price USD 75, $67.50 at Amazon.com, £40.50 at Amazon.co.uk Zhou is a professor at the University of Houston. His book leans towards imaging and velocity analysis — it's not really about interpretation. If you're into signal processing and tomography, this is the book for you. Mostly black and white, the book has lots of exercises (no solutions though). ### Seismic Amplitude: An Interpreter's Handbook Rob Simm & Mike Bacon (2014). Cambridge University Press, 279 pages, ISBN 978-1-107-01150-2 (hardback). List price USD 80,$72 at Amazon.com, £40.50 at Amazon.co.uk

Simm is a legend in quantitative interpretation and the similarly lauded Bacon is at Ikon, the pre-eminent rock physics company. These guys know their stuff, and they've filled this superbly illustrated book with the essentials. It belongs on every interpreter's desk.

Enwenode Onajite (2013). Elsevier. 256 pages, ISBN 978-0124200234. List price USD 130, $113.40 at Amazon.com. £74.91 at Amazon.co.uk. This is the only book of the collection I don't have. From the preview I'd say it's aimed at undergraduates. It starts with a petroleum geology primer, then covers seismic acquisition, and seems to focus on processing, with a little on interpretation. The figures look rather weak, compared to the other books here. Not recommended, not at this price. NOTE These prices are Amazon's discounted prices and are subject to change. The links contain a tag that gets us commission, but does not change the price to you. You can almost certainly buy these books elsewhere. Comment ### Matt Hall Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning. # January linkfest Time for the quarterly linkfest! Got stories for next time? Contact us. BP's new supercomputer, reportedly capable of about 2.2 petaflops, is about as fast as Total's Pangea machine in Paris, which booted up almost a year ago. These machines are pretty amazing — Pangea has over 110,000 cores, and 442 terabytes of memory — but BP claims to have bested that with 1 petabyte of RAM. Remarkable. Leo Uieda's open-source modeling tool Fatiando a Terra got an upgrade recently and hit version 0.2. Here's Leo himself demonstrating a forward seismic model: I'm a geoscientst, get me out of here is a fun-sounding new educational program from the European Geosciences Union, which has recently been the very model of a progressive technical society (along with the AGU is another great example). It's based on the British outreach program, I'm a scientist, get me out of here, and if you're an EGU member (or want to be), I think you should go for it! The deadline: 17 March, St Patrick's Day. Darren Wilkinson writes a great blog about some of the geekier aspects of geoscience. You should add it to your reader (I'm using The Old Reader to keep up with blogs since Google Reader was marched out of the building). He wrote recently about this cool tool — an iPad controller for desktop apps. I have yet to try it, but it seems a good fit for tools like ArcGIS, Adobe Illustrator. Speaking of big software, check out Joe Kington's Python library for GeoProbe volumes — I wish I'd had this a few years ago. Brilliant. And speaking of cool tools, check out this great new book by technology commentator and philosopher Kevin Kelly. Self-published and crowd-sourced... and drawn from his blog, which you can obviously read online if you don't like paper. If you're in Atlantic Canada, and coming to the Colloquium next weekend, you might like to know about the wikithon on Sunday 9 February. We'll be looking for articles relevant to geoscientists in Atlantic Canada to improve. Tim Sherry offers some inspiration. I would tell you about Evan's geocomputing course too... but it's sold out. Heard about any cool geostuff lately? Let us know in the comments. Comment ### Matt Hall Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning. # All you want for Christmas It's that time again! If you're tired of giving the same old rocks to the same old geologists, I've got some fresh ideas for you. ### Stuff • My wife came back from town recently with this spectacular soap, from Soap Rocks. I mean, just look at it. It's even better in real life. • You just can't go wrong with a beautiful hammer, like this limited edition Estwing. Don't forget safety glasses! • Or go miniature, with these tiny (Canadian!) hammers in gold ($859) or silver ($249). Steepish prices, but these aren't exactly mainstream. • More jewellery: geode earrings. Hopefully not too massive. ### Tees It's the obligatory t-shirt collection! Here are some that jumped out at me — and one of them is even a bit geophysical. Available from (left to right) Threadless (here's another fun one), Etsy, and Metropark. ### Books... and non-books • There are loads of books in our reading list — some of them are essential, and some are totally workable as gifts. • It would be remiss of me not to mention our own new book, 52 Things You Should Know About Geology — perfect (I think, but I would say that) for students and professionals alike, especially those in applied/industrial geoscience. • I'm a big fan of Edward Tufte's beautiful books about data visualization, and they are now available in paperback. All four books for$100 is truly a bargain.
• It's not a book exactly, but I do like this minerals poster. Although less useful, this arty version is even prettier... and this cushion is verging on spectacular.

### Goggle box

Tired of reading about geology after cranking through papers or dissertations all day? TV has rocks too! There's Iain Stewart's various series (right — Earth, 2009, and How To Grow A Planet, 2011) for some quality BBC programming. If you're in Canada, you might prefer CBC's Geologic Journey, 2011 — inexplicably hosted by a non-geologist. The Discovery Channel made Inside Planet Earth, 2009 but I've never liked their stuff. some of this stuff might even be on Netflix...

### Kids' stuff

Kids like geology too. A Rock Is Lively manages to be beautiful and informative, Rocks: Hard, Soft, Smooth, and Rough focuses on the science, and If Rocks Could Sing is just cute. If it's toys you're after, you can start them young with this wooden stacking volcano, or you could go for this epic Lego globe... (not for the half-hearted: it will require you to load the Digital Designer file and order a large number of bricks).

Still stuck? Try my Christmas post from last year, or the year before, or the year before that. I highly recommend Evelyn Mervine's posts too — loads more ideas there.

The T-shirt and book cover images are copyright of their respective owners and assumed to be fair use. The soap picture is licensed CC-BY.

Comment

### Matt Hall

Matt is a geoscientist in Nova Scotia, Canada. Founder of Agile Scientific, co-founder of The HUB South Shore. Matt is into geology, geophysics, and machine learning.

# 52 Things is out!

The new book is out! You can now order it from Amazon.com, Amazon.co.uk, Amazon in Europe, and it will be available soon from Amazon.ca and various other online bookstores.

What's it about? I sent Andrew Miall some chapters at the proof stage; here's what he said:

Geology is all about rocks, and rocks are all about detail and field context, and about actually being out there at that critical outcrop, right THERE, that proves our point. The new book 52 Things You Should Know About Geology is full of practical tips, commentary, and advice from real geologists who have been there and know what the science is all about.

### Amazing authors

A massive thank you to my 41 amazing co-authors...

Eight of these people also wrote in 52 Things You Should Know About Geophysics; the other 34 are new to this project. Between them, this crowd has over 850 years of experience in geoscience (more remarkably, just two of them account for 100 years!). Half of the authors are primarily active in North America; others are in the UK, Germany, Indonesia, India, the Netherlands, and Norway. Ten are engaged in academia, four of them as students. The diversity is wonderful as far as it goes, but the group is overwhelmingly composed of white men; it's clear we still have work to do there.

We have the globe mostly covered in the essays themselves too. Regrettably, we have gaping holes over South America and most of Africa. We will endeavour to fix this in future books. This map shows page numbers...

### Giving back

Academic publishing is a fairly marginal business, because the volumes are so small. Furthermore, we are committed to offering books at consumer, not academic, prices. The 42 authors have shown remarkable generosity of time and spirit in drafting these essays for the community at large. If you enjoy their work, I'm certain they'd love to hear about it.

In part to recognize their efforts, and to give something back to the community that supports these projects (that's you!), we approached the AAPG Foundation and offered to donate \$2 from every sale to the charity. They were thrilled about this — and we look forward to helping them bring geoscience to more young people.

These books are all about sharing — sharing knowledge and sharing stories. These are the things that make our profession the dynamic, sociable science that it is. If you would like to order 10 or more copies for your friends, students, or employees, do get in touch and we will save you some money.