►
From YouTube: EOSC 350 EM Lecture 3
Description
Third lecture on electromagnetics by Doug Oldenburg. EM-31 system.
A
A
So
what
I'd
like
to
do
today
is
to
do
like
just
it's
been
a
few
minutes
right,
beginning
kind
of
highlighting
the
two
important
things
that
really
want
you
to
kind
of
grasp
jitteriness
with
respect
to
the
electromagnetic.
Then
we
have
an
instrument
here
called
V.
This
is
the
e
m31
is
probably
the
most
commonly
use
instrument
for
site
characterization
and
for
environmental
concerns.
A
A
And
I
think
that's
a
perfect
segue
into
a
project
that
we
did
a
number
of
years
ago
on
the
expo
site.
I
think
there's
a
lot
of
similarities
and
yeah
then
might
talk
to
you
a
little
bit
about
other
types
of
sources,
transmitters
and
receivers
that
that
are
common,
that
you'll
come
up
with,
but
anyway
that's
that's
the
objective.
So
first
of
all,
I
just
want
to
kind
of
briefly
recap:
the
a
couple
of
the
important
items
here.
A
So
the
first
there's
two
kind
of
parts
of
this.
The
first
is
kind
of
the
e
amp
induction
part,
whereby
we've
got
some
kind
of
a
transmitter
and
it
induces
currents
into
an
object
down
here.
Let's
play
drum
and
that
sets
up
currency
in
here
and
those
currents
produce
another
magnetic
field
that
can
be
measured
anyplace.
A
So
that's
the
e/m
conduction
part,
and
for
that
these
pictures
and
the
lab
should
kind
of
reinforce
the
whole
concept
about
mutual
flux
and
coupling
so
that
you
could
with
Lenz's
law,
understand
you
know
what
directions
of
currents
would
be
moving
in
the
object
and
then
what
the
directions
are
for
the
subsequent
magnetic
fields
and
that
would
actually
allow
you
to
sketch
out
a
curve
that
looks
like
this
if
you
rent
over
it.
So
that's
that's
an
important
thing.
A
If
you
get
that,
then
I
think
you've
got
a
lot
of
the
basic
aspects
about
genetic
induction.
The
second
part
of
that
was
that,
depending
upon
whether
that
object
is
really
conductive
or
just
moderately
conductor
to
the
response
gets
put
into
either
the
real
part
or
the
imaginary
part
of
the
signal.
So
remember
that
signal
it's
coming
back
as
a
sinusoid
and
it's
got
a
bit
of
a
phase
delay
with
respect
to
the
transmitter,
and
so
there's
a
certain
part
of
that.
A
A
A
So
it's
going
to
come
out
on
this
instrument
that
this
one
here
goes
to
the
parent
conductivity
and
that
is
going
to
occur
so
long
as
the
separation
between
your
your
coils.
If
this
separation
is
much
greater
first
rate,
if
the
separation
is
much
less
than
the
skin
depth,
so
the
skin
depth
was
that
depth
into
the
earth
at
which
this
signal
falls
off
by
1
upon
Delta.
A
A
So
that's
all
the
first,
that's
all
the
first
part.
The
second
part
is
that
whenever
we
have
a
transmitter,
then
there's
gonna
be
a
certain
amount
of
signal
that
goes
out.
There's
going
to
be
a
region
around
here
which
is
sort
of
in
the
sensitivities
of
whatever
my
transmitter
is
so
that's
important
to
kind
of
qualify
under
special
conditions.
When
the
earth
is
really
layered,
we
can
actually
compute
what
the
sensitivity
function
is
for
just
a
homogeneous
earth
and
that
sensitivity
function
looks
like
this
and
what
is
this
there?
This
axis
is
normalized
depth.
A
A
The
maximum
sensitivity
is
about
point
four.
So
if
I've
got
a
separation
here
of
three
meters
point
four,
that
means
that,
as
you
know,
I'm
really
mostly
sensitive
to
what's
happening
about
a
little
bit
over
a
meter
in
depth.
So
you
can
see
that
an
instrument-
that's
got
fairly
small
s
and
it's
curve
that
looks
like
that.
You're
only
going
to
see
down
a
couple
of
meters,
three,
four
five
meters,
the
sensitivity
function
depends
upon
what
the
orientation
of
the
transmitter
is.
A
A
A
I've
got
different
orientations
of
my
transmitter/receiver
I
get
different
ways
of
of
sensing
here.
So
why
might
this
be
important
for
the
following
reasons
that
the
apparent
conductivity
that
you
obtain,
whether
it's
can
millisiemens
per
meter
or
whatever
is
really
the
number?
That
is
how
you
think,
but
it's
sort
of
the
integral
of
this
sensitivity
function
with
respect
to
whatever
conductivity
that
was
there.
So
the
idea
is
you
get
a
number
out
here,
which
is
an
integral
of
this
kind
of
a
function
with
Sigma.
A
The
important
thing
to
remember
is
that
this
sensitivity
function
actually
gets
it's
kind
of
something
that's
attached
to
the
instrument
itself.
So
if
the
instrument
goes
up,
then
the
sensitivity
function
stays
with
it
so
that
the
amount
that's
in
the
ground
part
of
sensitivity
function
in
the
ground
is
this
small.
So
he
tried
to
show
that
in
the
lab.
A
You
can
raise
the
boom
up
higher
or
lower,
and
you
can
for
different
conductivity
z'
that
structures
that
you
have.
In
other
words,
if
the
conductivity
structure
was
like,
this
see
how
it
was
resistive
and
then
it
was
conductive
and
the
sensitivity
function
looks
like
this,
then
the
number
that
you
get
out
insert
of
the
integral
of
this
product,
which
looks
like
this.
It
actually
turns
out
to
be,
in
this
case
a
pretty
low
number
compared
to
what
the
conductivity
value
is
of
this
layer
that
you
have
up
here.
A
Something
you
said
it
looks
heavy,
it's
not
that
heavy.
If
you
just
lift
it
up,
but
it
is
heavy
if
you're
walking
with
it
for
eight
hours,
so
you
simply
go
around
and
there
is
a
data.
Logger.
That's
that's
attached
here
and
then
you
just
need
to
simply
walk
along
like
this,
and
you
have
your
lines
out
in
particular
direction,
and
you
know
you
actually
have
the
option
of
deciding
how
you
want
to
to
collect
the
data.
So.
B
A
A
0.1
cm
per
meter,
if
my
instrument
is
right
on
the
ground,
I'm
going
to
get
an
apparent
conductivity,
that's
equal
to
that.
If
my
instrument
is
up
higher
I'm
going
to
gradually
jet
one
jet
is,
it
is
much
less.
Similarly,
if
I
have
a
layering
space,
so
if
this
is
say
the
wunens
and
Sigma
2,
now
my
sensitivity
function.
A
A
You
can
see
that
you
get
different
information
if
I
actually
took
two
numbers.
If
I
took
one
in
which
the
instrument
was
right
on
the
ground,
I'd
get
something
and
that
would
be
averaging
whatever
layered
structure
of
got.
If
I
lift
it
up,
I'd
be
getting
a
different
averaging,
so
I
get
different
numbers
and
you
could
think
that
maybe
you'd
be
able
to
combine
those
numbers
and
give
you
information.
You
know
about
maybe
the
individual
conductivity
and
the
and
that
lated
thickness
also
that
sensitivity
function
if
I've
changed.
The
orientation
of
the
coil
looks
different.
A
By
doing
falling,
if
I,
if
I
set
the
instrument
right
down
here
on
the
ground,
I'm
going
to
get
one
reading
now,
I
might
be
pulling
it
up
like
this.
I'm
going
to
get
a
different
reading,
I'm
sample
a
year
differently.
If
I
turn
the
guy
on
its
side
like
this
again,
it's
going
to
be
different
and
if
I
put
it
down
like
this,
is
there
so.
A
Four
different
numbers
and
if
I
have
let's
say
a
layer
over
a
half
space,
this
is
gives
me
one
parameter
me
another
parameter
and
a
layer
thickness
that
we
have
three
parameters.
I
have
four
numbers
you
can
find.
What
do
you
may
believe
that?
So
that's
the
idea
of
kind
of
the
sensitivities
and
what
what
the
instrument
do.
A
A
Are
different,
this
is
actually
in
conductivity.
This
is
just
in
units
of
volts
per
meter,
and
you
know
it's
a
different
map.
The
importance
of
this
that
it's
mostly
used
for
trying
to
find
you
know
big
conductors
or
metallic
objects.
So
this
is
kind
of
like
a
male
finder,
and
this
is
actually
telling
you
something
about
the
conductivity.
A
Okay,
so
with
that,
I
want
to
just
sort
of
introduce
very
briefly
where
we
want
to
go
a
little
bit
of
a
background
on
this
and
then
Chris
is
going
to
tell
a
little
bit
of
his
project
now
come
back
to
the
to
the
X
website.
So,
as
you
I'm
sure
know
that
in
Expo
in
1986
Vancouver
and
this
great
big
exposition,
that's
the
time
that
Vancouver
really
became
on
the
world
map
in
the
region
down.
A
This
is
false.
This
is
all
false.
Creek
areas
or
anything
was
built
up.
Plasm
nations
still
exist.
Here's
Science
Center
everything
else
was
completely
void.
There
was
a
BC
Place
Stadium,
with
a
different
with
the
different
room
and
the
whole
place
was
actually
quite
marvelous
and
for
five
months
all
the
countries
the
world
were
there,
and
it
was
just
a
happening
that
and
then,
after
after
that,
after
everything
went
away
and
they
decided
okay,
we're
going
to
rebuild
this
area,
so
that
had
prompted
them
to
look
at
what
was
going
on
in
here.
A
A
A
A
A
A
B
Right
so
far,
a
capstone
project,
we're
we've
been
given
a
contaminated
site
in
Vancouver,
and
it's
located
near
the
Falls
Creek
area.
It's
actually
on
the
south
side
of
the
the
Falls
Creek
area,
it's
close
to
the
Olympic
Village.
So
it's
similar
in
terms
of
what
was
done
prior
to
the
Olympics
here
in
Vancouver
and
where
they
just
went
ahead
and
reclaimed
that
entire
section
here
in
the
South
right
between
I
guess
can
be
bridge
and
Main
Street
Main
Street.
And
so
we
don't
want
any
exactly
know
where
our
site
is.
B
B
Here
at
60
meters,
by
37
meters
and
this
area,
this
general
area
is
about
200
to
300
meters,
I'm,
sorry,
300,
200
meters,
we've
had
a
range
of
industrial
and
commercial
activities
in
this
area
over
the
past
hundred
to
150
years
on
our
specific
site,
which
we've
been
contracted
to
remediate,
there's
a
film
processing
laboratory,
that's
filling
in
still
working
and
we've
also
had
a
machine
shop
and
welding
on
that
site.
In
addition
surrounding
our
site,
our
other.
C
B
Yeah
dry,
cleaning,
automotive
repair-
and
this
has
led
to
us,
assuming
that
there
might
be
these
potential
contaminants
on
our
site,
and
so
we
have
to
look
at
testing
for
them
and
then
remediating
the
site,
if
need
be
based
on
the
standards
that
BC
has
for
contaminated
sites,
which
came
into
effect
after
Expo
86.
So
essentially,
what
pushed
for
all
the
center's
that
we
have
not
today,
and
so
we
really
didn't
look
at
geophysics
per
se
in
terms
of
how
we
would
test
for
these
contaminants.
B
We
assume
that
they
be
tested
for
looking
at
groundwater,
sampling,
soil
sampling,
but
I
guess
you
can
explain
how
the
Expo
86
case
history.
They
essentially
used
geophysics
tilith
forests,
then
she
buried
petroleum
tanks.
There
was
also
form
of
rail
way
in
this
area,
so
they
were
looking
for
actual
like
pieces
of
metal.
Besides
just
the
containers
that
would
have
housed
any
contaminants
of
pipelines
as
well.
B
B
B
C
C
B
So
yeah,
so
all
of
this
area
is
historically
up
here
and
we
have
to
Clark
Drive,
and
so
that
has
all
been
in
filled
with
gravel
sand
and
you'll
see
in
the
case,
history
from
Expo
86.
That
they've
also
found
just
like
would
trash.
That's
obviously
complicated
that
complicated
that
case
history
and
I'm,
not
sure.
For
our
case,
we
haven't
look
through
the
data
to
determine
if
we
would
have
anything
besides
fill
in
just
the
regular
till.
B
C
On
our
proposal,
we've
kind
of
gone
with
drilling,
bulldoze
up
to
a
depth
of
about
20
meters.
That,
from
a
resurgence,
showed
us
that
that
will
enable
us
to
collect,
go
deep
enough
to
collect
enough
groundwater
samples.
So
we
don't
exactly
know
how
deep
it
is,
but
from
our
from
like
using
new
pollutants
up
like
getting
elevation
of
the
ground,
except
we
didn't
mind,
a
twenty
meters.
Depth
would
be
appropriate
for
you
sit
down
water.
A
A
So
I
think
there
was
a
lot
of
things
that
probably
happen
there.
That
also
happened
north
of
here.
This
is
sort
of
the
northern
part
that
Chris
was
talking
about.
This
line
that
goes
through
here
is
actually
where
the
water
used
to
be
so
virtually
all
of
the
stuff
in
the
sort
of
southern
end
of
false
false
Creek
area
has
all
been
in
fill
just
about
everything
you
could
imagine
so
there's,
maybe
there's
gas
manufacturing
plants
in
here.
There
was
all
those
kinds
of
sawmills.
There
was
electric
rail
lines
that
were
going
through.
A
There
was
substations
there
to
try
to
work
with
transformers
and
a
lot
of
those
transformers
they
had
to
drain
the
dielectric
fluids
out
of
them.
Those
contain
PCBs,
that's
the
main
issue.
That
was
what
was
involved,
and
it
was
lots
of
wood
waste
because
they
were
just
trying
to
fill
things
in.
So
virtually
everything
that
you
can
imagine
was
what
was
done.
A
What
prompted
all
of
this-
and
this
may
have
a
lot
of
lot
of
people-
is
that,
after
Expo
six,
when
they
went
in
to
kind
of
do
the
site
characterization
they
do
what
they
usually
do.
They
they
go,
and
you
know,
do
a
couple
of
trenches,
so
they
they
dug
this
trench.
It
was
only
you
know,
ten
inches
wide
or
something
like
that
and
a
few
feet.
A
Deep
and
after
couple
minutes,
they
started
to
notice
that
there
was
oil
that
was
coming
in
and
in
fact,
in
some
places
where
they
were
digging
yeah,
you
could
get.
You
know,
sort
of
like
a
number
of
liters
per
minute
of
this
stuff
and
at
that
point
everything
basically
just
shut
down,
and
then
they
decided
that
they
needed
to
to
do
something.
So
this
was
at
the
time
that
we
were
just
getting
into.
A
You,
know
environmental
geophysics
at
UBC,
and
we
got
kind
of
excited
about
what
we
might
possibly
do
there,
and
so
we
thought
well,
let's
see
if
we
can't
go
down,
take
a
whole
bunch
of
different
geophysical
equipment
down
and
see
what
we
can
see.
But
from
the
first
thing
that
you
do
with
any
of
this,
you
try
to
do
some
background.
Reading
on.
You
know
what
the
site
was
like
and
we
managed
to
get
a
few.
You
know
pictures
of
things
that
at
least
showed
what
was
there
from
a
number
of
early
Excite.
A
So
this
was
1902.
There
was
a
glazing
plant
up
here.
In
most
everything,
I'll
show
you
there's
a
red
outline
here.
It's
100
meters
by
100
meters.
So
it's
a
little
bit
a
little
bit
bigger
than
what
you
guys
are
doing
the
old
water
line.
This
was
where
water
was
at
Shoreline.
Woods
was
up
in
here,
and
there
was
SAP
ssin
floors.
Factory
over
here
drive
killins
early
nineteen
nineteen
hundred's.
The
time
you
get
to
1936.
A
A
Far
more
infrastructure,
as
you
get
by
trying
to
get
up
to
1952,
there's
lots.
These
things
are
all
real
lines.
This
was
a
place
where
they
have
some
diesel.
Electric
electric
car
trade
cars
and
they
were
revamping
them
here
of
importance
to
us-
is
that
there
was
an
oil
house
that
was
sitting
in
here
and
what
they
would
do
with
these
oil
houses.
Is
they
use
them
to
drain
the
these
transformers
and
they
popped
the
oil
someplace
and
tried
to
kind
of
clean
it
up
and
then
do
something
with
it.
A
A
Trying
to
get
61
again,
things
have
to
change
still
like
the
oil
house,
more
storage
out
here
and
the
gas
plants
down
there,
and
then,
by
the
time
you
get
to
74,
we've
got
BC
Hydro
in
there,
which
means
that
you're
going
to
have
lots
of
wires
and
yeah
everything
you
can
imagine
so
lots
of
things
that
went
on
in
the
initial
filling
up
of
this.
This
whole
region
is
christmasing.
A
They
just
took
everything
they
got
and
you've
got
lots
of
all
wood
works
and
cement
or
whatever
else
you
just
there's
here's
a
picture,
for
instance,
of
just
kind
of
what
the
area
looked
like.
This
is
a
great
thing:
yeah
clawing
up
the
wood,
just
sort
of
feeling
stuck
in,
so
you
can
imagine
it.
Everything
is
there,
and
here
is
a
slightly
expansive
area
of
what
was
going
on
at
the
time,
and
this
is
the
region
that
we're
interested
here.
Here's
the
ayah.
A
When
they
done
the
first
hole
or
they
did
the
trash,
the
trenching
was
was
up
in
here
and
here's
where
they
found
the
the
oil.
That
was
that
that
was
coming
in
subsequent
to
that
they've
kind
of
determined
that
maybe
this
region
in
here
was
kind
of
oil
contaminated.
The
oil
seems
to
flow
it
on
top
of
the
water,
and
then
water
table
goes
up
and
down.
That's
usually
like
one
to
three
meters
in
depth,
and
it
was
the
soil
that
was
in
that
fluctuating
water
table.
A
A
The
same
is
true
with
you
know:
electrical
conductivity,
you
know,
we've
got
we're
growing
on
the
surface
and
then
there's
a
little.
You
know
something.
That's
buried
or
you've
got
a
nice
layered
structure.
Things
are
things
are
kind
of
simple
when
you
look
to
see
what's
happening
in
a
cross-section
at
the
expo
site.
However,
you
see
well,
things
are
really
much
more
complicated
and
that's
actually
I
think,
probably
very
similar
to
what's
going
on
it.
Christmas
Thanks.
This
is
a
vertical
cross-section
from
the
bottom.
We've
got
the
tail
layer.
A
So
at
this
point,
you're
we're
fine
and
then
we
gradually
go
up.
The
surface
has
got
fill
this
material
up.
Here
is
just
here's
where
you
Oh
everything
from
cement
slabs
to
wood
products,
to
virtually
everything
you
can
think
about,
is
sort
of
up
in
in
this
region
here
and
then
you've
got
a
clay
silk
under
here.
So
that's
that's
natural
and
then
we've
got
got
the
tilt
from
the
point
of
view
of
site,
characterization
and
stability.
It's
really!
You
know
the
depths
of
the
till.
That's
that's
important,
so
we
thought
well.
A
The
top
part,
for
instance,
actually
turned
out
not
to
be
simple
as
all
the
top
oh
good,
1/2,
meter,
close
to
a
meter
was
actually
filled
with
two
layers
of
concrete,
so
that
had
been
paved
over
at
one
point
and
then
you
know
somebody
put
some
dirt
over
top
and
then
they
ended
up
kV
again,
so
we
were
trying
to
put
holes
in
the
ground.
Just
to
you
know,
get
energy
Elector,
try
to
put
electrical
currents
in,
and
you
know
remember,
sitting
up
there
with
drills
and
trying
to
drill
a
hole
through
the
stuff.
A
A
Okay,
so
for
finding
this
guy
here,
so
the
depth
of
the
till,
we
thought
well,
there
should
be
a
real,
both
the
velocity
contrast
across
here,
as
well
as
maybe
a
conductivity
contract.
So
we
were
trying
to
that.
So
we
get
a
seismic
seismic
refraction
across
across
here
on
the
line
it
took
a
fair
while,
but
we
managed
to
get
get
some
data
I
GPR
we
did.
A
We
did
something
called
VL
ass,
which
I
haven't
talked
about.
I
might
get
not
sure
you
talking
a
little
bit,
that's
sort
of
a
natural
it.
It's
an
electromagnetic
frequency
domain
system
that
is
given
up
by
these
big
antennas
for
communicating
with
submarines,
so
assertively
the
energy
source.
So
this
is
this:
isn't
you
know,
experiment
and
we
did
gravity
and
we
tried
to
do
a
magnetics
experiment,
but
the
the
magnetometer
that
you
have
on
the
beach
this
proton
precession
magnetometer.
We
took
that
out,
thought
we'll
that'd
be
great,
we'll
use
that
turned
out.
That
was.
A
We
couldn't
use
that
at
all,
and
the
reason
for
that
is
that
that
magnetometer
only
works.
If
the
you
know,
the
gradients
are
not
too
large,
and
there
is
so
much
metal
and
stuff
down
there
that
the
magnetic
field
was
changing,
hugely
and
and
cause
the
magnetometer
to
produce
poor
results.
In
the
case
history,
in
the
on
the
GPG,
there
is
a
gradient
magicked
ometer
and
that
provided
the
son,
some
information
and
yeah,
then
we
did.
A
We
try
to
deceive
resistivity,
which
we
haven't
seen
yet,
but
you'll
see
next
next
week
and
that
basically
failed
because
we
couldn't
get
Anthony
on
the
ground
because
of
all
of
these
cement
slabs.
So
the
point
about
that
was
that
okay,
you've
got
a
background
here
that
you
might
be
able
to
get
you'll
make
some
distinction.
A
In
particular,
the
object
was
to
try
to
find
the
exhibit
ill
and
there's
a
whole
bunch
of
techniques
which
one
to
use
and
potentially
lot
of
these
are
possible,
but
some
work
better
than
others
and
are
more
useful
and
it
turned
out
that
the
oldest
technology
that
exists
is
in
this
guy.
Here
is
the
m31
and
didn't
you
come
on
to
our
RadarScope
until
close
to
the
end
of
well
of
our
planning
of
this?
Just
because
we
thought
wow,
that's
just
too
simple
an
instrument.
A
It's
just
not
going
to
it's
not
going
to
do
the
kind
of
thing
that
we're
going
to
do
we're
going
to
do
3d
stuff
here
right,
but
in
the
end
this
guy
was
the
most
probably
produced
the
most
useful
data
and
you've
seen
this
picture
before.
But
I've
got
some
few
more
things
to
talk
about
what
we're
looking
at
here
is
so
now
you
mentioned.
A
A
C
C
A
Because
you
understand
how
this
m31
works,
you
might
think.
Oh
well,
there's
something
there's
something
there
that
is
worth
investigating.
So
just
by
simply
looking
at
the
signatures
here
and
the
patterns,
you
get
the
idea
that
there
might
be.
You
know,
maybe
some
kind
of
a
conductor
that's
coming
up
through
here
and
maybe
something
that's
that's
you
so
that's
first
thing
the
other
is
we
could
walk
in
a
different
direction
so,
instead
of
having
the
north-south,
we
could
go
east-west
and
that
of
course,
excites
things
in
a
different
manner.
A
And
if
you
look
at
this
picture
versus
this,
so
this
inner
self-
that's
that's
the
east-west.
This
is
just
kind
of
smooth
out
in
and
it's
just
some
kind
of
a
positive.
That's
the
same!
That's
what
you'd
expect
if
you
had
a
so
if
you
had
a
conductor
that
was
going
in
here
and
you're
walking
this
way
parallel
to
it,
then
you're
kind
of
always
at
that
constant
distance
from
the
conductor-
and
you
tend
to
get
things-
are
elongated
like
this.
A
The
thing
that
we
weren't
more
successful
with
was
looking
at
the
conductivity
and
trying
to
find
where
the
hydrocarbon
might
be
so.
The
thing
about
oil
is
that
it's
resistor
on
this
apparent
conductivity
plot
up
here.
You
can
see
that
there's
this
blue
region
here
and
that
indicates
that
we've
got
very
low,
apparent
conductivity
and
when
they
did
the
test
hole
that
test
hole
was
done
right
up
in
in
this
region
in
here,
and
that's
where
the
the
oil
was.
A
So
our
idea
was
that
we'd
be
able
to
look
at
where
this
contaminating
or
low
resistivity
region
was
in
this
region
up
here
and
kind
of
compare
that
with
what
was
obtained
for
billing,
and
for
that
reason
we
kind
of
outline
the
region
out
here
where
the
oil
contaminant
was
importantly
for
that
now.
What
we're
trying
to
do
is
not
find
an
object,
but
we're
actually
trying
to
characterize.
You
know
an
earth
that
is
you're
more
or
less
uniform
horizontally.
A
With
respect
to
this,
this
contaminant,
and
one
way
that
you
can
make
some
assessment
of
that
is
to
orient
booms
in
two
different
directions.
If
I
have
it
north-south
or
east-west
and
I
get
the
same
apparent
conductivity
that
I
could
be
thinking.
Well,
things
are
pretty
pretty
uniform
in
here
as
I'm.
Sorry.
Well,
maybe
that's
a
good
estimate
for
what
that
pair
conductivity,
which
is
different
than
here
of
course
right.
So
here,
if
I've
got
the
boom
orange
of
north-south
or
east-west
I
get
very
different
numbers.
A
We
get
very
large
negative
values
in
certain
places
and
those
are
indicative
of
really
high
conductivity
and
probably
metal,
and
in
fact,
if
you,
if
you
kind
of
look
at
these
maps
and
just
circle,
the
places
where
you've
got
these
extreme
values-
and
you
say
well-
that's
probably
no
either
they're
pretty
close
to
right.
So
the
end
of
the
day
we
end
up
with
with
the
following
there's
some
conductors
that
are
coming
in
here.
A
A
A
They
found
that
it
was
concrete
with
massive
rebar
I've,
never
seen
rebar,
that
sceptic,
it
was
probably
inch
and
a
quarter
thick
and
just
know
tons
of
these
things,
I'm
not
sure
what
they
were
trying
to
be,
of
course,
but
a
lot
of
this
stuff
in
here
was
eventually
explained
and
there's
metallic
objects
down
in
this.
This
corner
here
which,
which
were
dug
up
so
I,
guess
the
thing
that
just
wanted
to
kind
of
recap
with
this
is
a
couple
of
things.
A
A
A
A
So
the
plan
is
that
we'll
have
a
tbo,
Wednesday
and
then
quiz
on
Friday,
so
at
the
quiz.
There's
there's
nothing
really
else
that
we
have
to
cover
in
here.
But
I
would
like
to
talk
just
a
little
bit
about
a
couple
of
other
transmitters
and
receivers,
different
kinds
of
surveys
that
you
might
come
across
and
then
that
will
finish
up
the
e/m
and
then
we'll
start.
The
PCB
stivity.