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12.221 Field Geophysics |
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Instructors Tom Herring, Brad Hager |
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IAP 2004 |
Description
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Practical
methods of modern geophysics including the Global Positioning System (GPS),
gravity. Field work is conducted in western US and includes intensive 8-day
field exercise. Focus is on measurement techniques and their interpretation.
Introduction to the science of gravity, and the GPS. Measure of crustal
structure, fault motions, tectonic deformations, and the local gravity field.
Students perform high-precision measurements and participate in data
analysis. Emphasis on the principles of geophysical data collection and the
relevance of these data for tectonic faulting, crustal structure, and the
dynamics of the earthquake cycle. This year's
camp will be held North of Blythe California. The camp will be located 34o03'45" N, 114o32'40"
W. |
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There is a
follow on communication intensive subject 12.222 that will be offered in the
Spring 2004 semester. This
course satisfies the EAPS CIM requirement. |
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Contacts: |
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Thomas
Herring, 54-618, 253-5941, tah@mit.edu |
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Brad Hager 54-622
253-0126, brad@chandler.mit.edu |
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Important Dates: Friday December 12, 2003 |
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$200.00 Fee due Carol
Sprague Room 54-912 253-3381.
Check made payable to MIT.
We need this check to make the flight reservations. |
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Course Schedule for IAP
2003 |
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Class |
Date |
Topic/Activity |
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1 |
01/05 |
Class 10-12
54-313: Introduction to course
material and camp logistics |
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2 |
01/06 |
Class 10-12
54-313: Basic GPS focusing on general
background and aspects needed for field camp |
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3 |
01/07 |
Class 10-12
54-313: Basic gravity concepts and
applications at field camp. |
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4 |
01/08 |
Class 10-12
54-313: Analysis of data from last
year's field camp and planning of measurements for this year. |
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5 |
01/09 |
Travel Day Boston-Palm
Springs. Meet in East Parking lot at 5:00 am. |
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6 |
01/10 |
Camp reconnaissance and
practice with gravimeter and GPS equipment. Regional gravity measurements. |
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7 |
01/11 |
Gravity survey: Two teams one
doing gravity and the other following with GPS. Night-time reduction of data |
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8 |
01/12 |
Static GPS: Preliminary
analysis of reduced gravity measurements using GPS heights |
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9 |
01/13 |
More gravity measurements |
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10 |
01/14 |
Static GPS |
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11 |
01/15 |
Gravity measurements in
morning. We leave camp
mid-afternoon. |
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12 |
01/16 |
Travel Day Palm Springs to
Boston |
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13 |
01/20 |
No class this
day. |
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14 |
01/21 |
Class 10-12
54-313: Modeling GPS and gravity data |
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15 |
01/22 |
Class 10-12
54-313: Meeting on analysis of data |
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16 |
01/23 |
Class 10-12
54-313: Final student reports: Oral
and written reports due from teams. |
Detailed Aims of IAP 2004
Course:
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This year's
camp will be held need Blythe California. We will be looking at two basic topics in the course (a) Measurement
of any motion of GPS marks in the region by comparison of our static GPS
measurements with results from previous GPS surveys and (b) Development of a
sub-surface model for the structure in the region using gravity measurements
collected at field camp with previous gravity measurements. Post-camp analyses will focus on
addressing these two problems and combining the data collected this year with
other data. We will be
interested in the possible effects of ground water use on the surface
positions of GPS monuments. |
Logical information:
Items to bring to camp:
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Valid
picture ID: Either driver's license or passport. Note: MIT ID or a copy of a passport is not acceptable form
of ID.
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Tent
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Sleeping bag
(long-range forecast is for mid-30 nights and 50-60 during day).
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Ground sheet/Sleeping
pad
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Sturdy boots
(sufficient to handle rough terrain)
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Sturdy pair of gloves
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Sturdy water bottle
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Hat for sun protection
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Flashlight (extra
batteries)
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Sun block and
moisturizer (air will be dry at 1000m altitude)
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Field notebook, pens, calculator
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Laptop computer if you
have one you want to bring
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Some snacks, trial mix,
gum (All food will be provided while in camp)
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Books to read during
"off-times"
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Personnel items and
clothing for 8 days in field.
Layering of clothing is best for day and night conditions.
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Swimming gear for stays
at hotels
Class
Notes
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Lec 01 |
Basic introduction to
class |
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Lec 02 |
Introduction the Global
Positioning System (GPS) |
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Lec 03 |
Introduction to Gravity
measurements. The chapter on gravity is here. |
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Lec 04 |
Planning for field camp. Plots show extent of existing
data. NGS
Data sheet entries for geodetic marks |
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Data |
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Data from the field camp
has been put on this web site: Vidal_FC_04
contains the files from the Mac at field camp Vidal_Dell_04
contains the m-files from the Dell PC and the grav_015.ht
The WGS-84 ellipsoidal
height of the Field camp base station is 234.448 m. |
Assignments
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Ass1: |
Due Tues Jan 6: |
Find out
what you can about GPS data and results obtained in near Blythe
California. Prepare a 1-page
summary for submission (Summary should also be emailed to tah@mit.edu with links included). |
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Ass 2 |
Due Thur. Jan 8 |
1)
Gravimeter practice 2)
Gravimeter problem set 3) Calculate
expected dial reading at field camp 4) Get tidal
corrections (1 person) 5) Maps for
Vidal quadrangle and vicinity: Topography
(DEM) Observed
gravity Free
air gravity Bouguer
gravity Isostatic
gravity Data file with gravity measurements The matlab directory contains some matlab programs that give
examples of the use of matlab for the class assignment (The m-files will need
to be changed). The dem
file that can be used in DEMplt.m is VIDAL_CA-24000.dem |