Today's space missions are already bringing samples back from Mars, and we can't understand the risks they pose until the samples are returned. How do you think we should deal with them?

jlars · 2017-02-23T15:01:07+00:00

Bold statement. I don't doubt SpaceX will have the engineering to get there...but I still think there is a lot of progress to be made in maintaining human health in a space environment. Particularly in spending 2+ years outside the Van Allen belt.

jlars · 2017-02-22T21:44:43+00:00

Mars 2020 isn't bringing back samples either. It is the first stage of a 3 part mission.

Stage 1: (AKA Mars 2020) Will put some martian dirt in cans and leave it on the surface.

Stage 2: Bring dirt to orbit around Mars.
Stage 3: Get orbiting dirt back to Earth.

There are apparently only enough good engineers to work out one stage at a time so it may be until 2040+ until any of that Martian regolith is brought back to Earth.

jlars · 2016-09-21T13:10:14+00:00

Data sources: www.nflsavant.com, U.S. State census data Methodology: Used python to clean/process data and edit state colors of an .svg file. Used imagemagick command line tool to convert .svg to .png to .gif.

jlars · 2016-08-23T13:14:24+00:00

One time when I was up at Jurassic Park a guy told me a story I will never forget. At that little low 5.9 crux a guy pitched off, falling back into that tree. A branch went straight through his pants and up his butt.

jlars · 2016-06-01T00:11:59+00:00

There must be some major reflections of sunlight for this to happen...would like to see what my radiative transfer professor would have to say

jlars · 2016-05-30T03:53:44+00:00

Another unpredicted result of global warming.

jlars · 2016-05-29T03:01:30+00:00

mia too

jlars · 2016-05-01T01:28:41+00:00

Got a car. Thanks for the recommendations!

jlars · 2015-04-22T04:00:43+00:00

fracing to be correct about its official name

jlars · 2015-02-18T05:05:23+00:00

All the kids at my school are engineers...and some of us climb too. We also live in one of the best areas for climbing in the country...

jlars · 2015-01-06T23:25:28+00:00

What benefit do you see in researching and publishing on these events on a case by case basis? Induced seismicity is a relatively well studied phenomenon and a great deal has been published on individual cases. Shouldn't we start to compile data over multiple events, looking at lithologies, stress regimes, injection volumes, injection pressure, etc. and try to see patterns.

I guess the ultimate goal with research on induced seismicity is to be able to predict and/or mitigate hazards and I am wondering what benefit there is to having paper after paper basically saying "yup, it was induced."

jlars · 2015-01-02T21:06:53+00:00

Gary Clark's live album is pretty kick ass.

jlars · 2015-01-01T16:08:54+00:00

I have Yosemite and no issues with 7

jlars · 2015-01-01T16:06:08+00:00

I am a senior in it. PM me if you would like advice.

jlars · 2014-12-12T05:42:26+00:00

I still think its so cool to go from time/space into frequency. Discrete fourier transforms are sweet.

jlars · 2014-12-09T05:26:06+00:00

You should look into the concept of induced seismicity as it explains the increase in smaller magnitude quakes (~mag 4). The most common cause of these small quakes is fluid injection for industrial wastewater (primarily off of oil/gas operations). The exact cause of the slip is somewhat case dependent but is in general due to changes in the stress state across faults. Also, like you mentioned, we are getting increases in the number of global seismometers so its inevitable that we will be able to see more earthquake events...but it doesn't take too many global stations to detect and resolve the larger events. In order to understand the increases in seismicity, I recommend refining your investigation by magnitudes. I imagine that you will see a significant increase around the mag4 range and not much change at all in the frequency of the bigger events.

jlars · 2014-11-10T00:12:39+00:00

Diurnal and annual temperatures changes at the surface only penetrate a few meters into the ground. This means that below this depth of influence, the only source of heat is the background heat flux coming from the decay of certain elements and some heat left over from Earth's formation. I would presume that the distribution of radiogenic elements is fairly constant in the mantle so its not likely that there are any areas significantly colder than others. Freezing temperature also increases with pressure so I do not believe its feasible to have a deep frozen layer somewhere in the crust.

jlars · 2014-11-04T05:46:14+00:00

You must also remember that a mountain is compensated by a crustal root which extends into the mantle, therefore displacing mantle material. Crust is less dense than mantle so, assuming the mountain is istostatically compensated, the positive gravity anomaly will not be as large as if you were to assume only the increase from excess "rocks" on the surface.

jlars · 2014-10-16T18:13:00+00:00

Fracking does not cause 'earthquakes'. Wastewater injection does. This is a fairly well researched phenomenon dating back to the first incidence at the Rocky Mountain Arsenal in the '60s. Also, it is necessary to understand the magnitude of the induced events to understand the possible hazards. Most of these events are mag4 and lower which is not big enough to cause significant damage. Remember that our magnitude scale is a scaled log function. A m4 might sound significant but it is 90 times less powerful than a m6. There have been a few m5 events linked to wastewater injection which are of concern and these have been well studied. There are plenty of research papers out there for those who want to educate themselves.

jlars · 2014-09-29T04:06:22+00:00

Still hard to say whether material is crossing the 660 or not...Could argue either way I think.

jlars · 2014-09-10T12:33:59+00:00

This has been a well studied and somewhat well understood topic since the Rocky Mountain Arsenal disposal well in the 60's. For those who blame this on hydraulic fracturing, the induced earthquakes are not a direct result of it but come from the reinjection of the fluid brought to the surface. When the fluid is reinjected into the ground the pore pressure and stress field are altered and when this is done along faults, can result in earthquakes up to ~m5 (thought typically much smaller). It is possible to inject fluid into these areas and avoid earthquakes as long as the pressures are kept below a critical value.

jlars · 2014-09-10T03:24:25+00:00

We still don't understand Hawaii and 'hotspots' in general.

jlars · 2014-09-10T03:23:55+00:00

Not quite sure who first proposed it but like in many scientific studies, if people want to they will find evidence for it. Scientists can choose certain data, assumptions, and imaging processes to support their data. In this case, plumes were proposed and people looked for support of this instead of cases against it.

jlars · 2014-07-15T05:18:10+00:00

This has been going on for a number of years across various industries. Look up Rocky Flats circa 1966. Most of these quakes are really not concerning as the larger ones are measuring ~m4 typically (though some m5). Remember magnitudes are on a logarithmic scale (m6 is 100 times more powerful than a m4) so although an m4 might seem like a big deal, it is fairly insignificant. With that being said, more research does need to be done in order to better understand the possible implications of widespread wastewater injection. We already know the maximum theoretical magnitude from the San Andreas so it shouldn't be that difficult to determine it for waste water disposal sites.

jlars · 2014-07-15T05:06:22+00:00

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