# Moontower #17

Friends,

I felt both earthquakes this past week in Palm Springs which is about 170 miles from the epicenter in Ridgecrest. It compelled me to review the chapter from Nate Silver’s Signal and the Noise discussing our inability to forecast earthquakes despite a long history of seers and scientists trying. What do we know?

• While we are confident in the statistical nature of aftershocks, when a large earthquake hits we still don’t know if it is the main event or a foreshock.
Earthquakes result from a buildup of stress along fault lines. It might follow that the stress builds up until it is discharged, like a geyser erupting with boiling water, relieving the stress and resetting the process. The fault system is complex: regions like California are associated with multiple faults, and each fault has its own branches and tributaries. When an earthquake does strike, it may relieve the stress on one portion of a fault, but it can transfer it along to neighboring faults, or even to some faraway portion of the same fault.
• We do not understand geological processes that cause earthquakes enough to construct models which can predict earthquakes. Without such bottoms-up simulations, we are left to rely purely on statistics of past earthquakes to predict them.
You can create a statistical variable called “stress” in your model. But since there’s no way to measure it directly, that variable is still just expressed as a mathematical function of past earthquakes
• We are able to approximate long-term averages. Enter the Gutenberg-Richter law.
There is a relatively simple relationship between the magnitude of an earthquake and how often one occurs. If you compare the frequencies of earthquakes with their magnitudes, you’ll find that the number drops off exponentially as the magnitude increases. While there are very few catastrophic earthquakes, there are literally millions of smaller ones.

If you graph earthquakes on a log scale with the Y-axis as frequency and X-axis as magnitude we see a “stunning regularity”.

Credit: Signal and the Noise
A power-law distribution emerges!

Something that obeys this distribution has a highly useful property: you can forecast the number of large-scale events from the number of small-scale ones, or vice versa. In the case of earthquakes, it turns out that for every increase of one point in magnitude, an earthquake becomes about ten times less frequent. So, for example, magnitude 6 earthquakes occur ten times more frequently than magnitude 7’s, and one hundred times more often than magnitude 8’s.

But now I must let you down. Even though we can approximate the frequency of earthquakes we can’t predict when and where they might occur.

• The official position of the USGS is even more emphatic: earthquakes cannot be predicted. “Neither the USGS nor Caltech nor any other scientists have ever predicted a major earthquake,” the organization’s Web site asserts. “They do not know how, and they do not expect to know how any time in the foreseeable future.”
Find your city and remember — these are long-term averages. There is no concept of “we are due for one”. And conversely, if we just had a big one, that does not mean we are due for a break.

credit: Signal and the Noise

Climb Higher

A lot of you know I had only had kids so that I would have future boardgame companions. I’d go as far as saying it was imperative to have an even number of family members to balance teams. Tragically, we have nobody to break voting ties (we have a history of crowdtexting friends to settle debates). The point remains — we like games in our household. A fun game I started playing with Zak this week is Evolution: The Beginning which is a junior version of a more complex game.

In Evolution: The Beginning, you’ll adapt your species to succeed in a dynamic ecosystem where food is scarce and predators roam. Traits like Flight and Horns will protect your species from Carnivores while a Long Neck will help them get food that others cannot reach. With hundreds of ways to evolve your species, every game unfolds in a beautifully unique way.

It’s a card game where you must manage populations of carnivores and herbivores as you try to eat the most food. The punch-counterpunch dynamic of the game maps faithfully to how predator-prey games in nature balance themselves. Concentrate too much on defensive traits and competing populations grow quickly. Modify a species to be an aggressive carnivore and more scavengers appear in the ecosystem. React and adapt. It imparts a beautiful sense of how evolution favors adaptation to the prevailing competitive landscape as opposed towards some march towards a higher form. An organism’s fitness is a purely relative concept. The game’s elegance mirrors nature well. And you can scoop it at Target.

Between the artwork and some memorizing, Zak (turning 6 this week) could play without being able to read fully. His interest and energy were bursting as the game started to ‘click’. I felt the same. Playing a game that is slightly out of reach is an avenue for learning that speeds downhill using his own enthusiasm as fuel. “Sit down and do workbook” is all uphill in molasses. I’m pretty excited to have passed the Candyland phase since a much richer world of learning lies within complex games.

The gaming world likes to point to the benefits of using games to practice computational thinking. Google for Education has an entire portal dedicated to the formal reasoning processes that you will be familiar with if you have coded, managed a project, or even planned a trip.

When playing games with kids, Evolution game designer Nick Bentley has great tips...

And if you want to connect IQ, its broader cousin “successful intelligence”, and gaming then read about “gameschooling“.

Last Call

• NASA has created a library of 140,000 high-definition files filled with photos, videos, and sound clips, all free and available for downloadI think this is a pretty cool source for photos to blow up and frame for your home.
• “The road to hell is paved with good intentions”. Or what economists refer to as the “cobra effect”. Here’s a quick explainer from the Sketchplanations letter I subscribe to.
• Going on a group vacation and need to divide expenses by subsets of groups and figure out who owes who before you all head back to reality? I highly recommend the Splitwise app. Very intuitive, handles many allocation methods, and even lets you Venmo one another right from the app!

From my actual life

Despite 105 degree temps, Palm Springs was a great family trip. Besides swimming and grilling, we loved:

• Palm Springs Air Museum. An amazing collection of war memorabilia, vehicles, and aircraft.
• Hiking at Joshua Tree with a pitstop in Pioneer Town afterwards. Pioneer Town has been a Western movie set for over 200 films. It’s about 5 blocks long and even has a few full-time residents!
• A 3.5 mile hike, gaining 1800 feet of elevation, up the North Lykken Trail at the San Jacinto Mountain in Palm Springs (thanks for finding that Mike). Despite a tough, hot trail a pair of almost 6-year-olds were able to handle it. Not quite complaint-free and John may have used a Ben and Jerry’s bribe, but they made it.
• Driving around to see famous homes (Sinatra, Elvis, a few presidents) and architecturally significant houses. Turns out we were staying right near the Kaufmann Desert House which I had known of because of Slim Aaron’s famous glamour photography (we have one of Slim Aaron’s Tahoe photos in our entryway). I enjoyed the wikipedia for the Kaufmann Desert House especially the bit about the restoration where a long-closed section of a Utah quarry reopened to mine matching stone. The wiki author states: many critics place the Kaufmann House among the most important houses of the 20th century in the United States, with the likes of Fallingwater, Robie House, Gropius House, and the Gamble House.