415-GeologyReport

Geologist's Report

Date: April 15, 2015

Crew Geologist's Name: Auriane Canesse

Hello Earth,

Here is a short summary of the progress of our geology experiment. I

will begin by explaining briefly the aim of our study and then I will

describe the results we have got so far.

The goal of our experiment is to map the magnetic susceptibility of

the ground in order to study its variation. The susceptibility varies

with the composition of the soil: it is quite low for sand but very

high for iron or water for example.

Today we wanted to map the surrounding of the hab but since Gaspard's

GPS didn't work we had to take positions by hand with a meter. Since

it was much slower than planed we took only two small sets of

measurements.

For the first one we mapped an area of 25x3m behind the hab. The

buried tank behind the hab appeared very well on the data. Therefore

our instrument could be used to find metallic buried objects. We were

also thinking of using it to find possible water leakage but since the

device measures approximately the first 1.5m of the ground this seems

rather unlikely.

For the second set of measurements we took measurements every 3m on

140m to see if there was a global change. But we only had only

insignificant variations around a constant mean. The magnetic

susceptibility of the ground seems quite uniform. We will try to take

new measurements at a totally new location to see if we measure

different values.

We also discovered that the talkies-walkies disturb the instrument

measurements: since it measures tiny variations of a magnetic field,

the electromagnetic waves (radio frequency) of the talkies are enough

to change completely the measurements. This added another challenge to

our task since we couldn't speak while measuring. This could also be a

great problem for automatic measurements (with the susceptibilimeter

connected to a computer) since then there would be no way to choose to

take the measurements when no one is speaking.