Week 2 Flashcards
(49 cards)
It is a point at which three lithospheric plates meet.
Triple Junction
Who invented the system of longitude and latitude and made a map of the spherical world?
Eratosthenes of Cyrene
This theorem is described to be the most general displacement of a rigid body with a fixed point is equivalent to a rotation about an axis through that fixed point.
Euler’s Fixed Point Theorem
What process allows rocks to record the Earth’s past magnetic field?
A. Sedimentation
B. Magnetization
C. Paleomagnetism
D. Crystallization
C. Paleomagnetism
What is the main function of a fluxgate magnetometer in magnetic surveying?
A. Detecting seismic waves
B. Measuring magnetic anomalies
C. Inducing magnetization
D. Elevation correction
B. Measuring magnetic anomalies
What law states, “for relatively small deformations of an object, the displacement or size of the deformation is directly proportional to the deforming force or load”?
Hooke’s Law
What is the primary characteristic of a dipole field in Earth’s magnetic field?
A. Complex structure
B. Multi-polarity
C. Simple, largely dipolar
D. Chaotic orientation
C. Simple, largely dipolar
It is aligned at 11.5 ° to the earth’s geographic north-south axis (spin axis).
A. Geomagnetic North
B. Best-fitting dipole
C. Dipole field
D. Geomagnetic South
B. Best-fitting dipole
How often is the IGRF updated?
5 years
The ratios between the sine of each angle and their corresponding velocity are equal to a constant called?
Ray parameter
A mountain in isostatic equilibrium must be compensated by a ______ between the surface and compensation depth.
mass deficiency
Which among the following is true about ground magnetic surveys?
A. Covers a relatively small area with 10 to 100 kilometer station spacing
B. Avoid metallic objects and power lines
C. Is cost-effective compared to other magnetic survey methods
D. All of the above
B. Avoid metallic objects and power lines
These are zones of charged particles trapped by the Earth’s magnetic field, providing a protective shield against harmful radiation.
Van Allen Radiation Belts
This triple junction is always unstable.
FFF
If four (4) or more plates meet at one point, the configuration is always ______ and the system will evolve into two (2) or more triple junctions.
unstable
Define geoid.
Reference surface equivalent to sea level.
What are the Geomagnetic North and Geomagnetic South?
Geomagnetic North – 79◦N, 71◦W
Geomagnetic South – 79◦S, 109◦E
What is the IGRF?
International Geomagnetic Reference Field (IGRF) – The internationally agreed values of the geomagnetic field.
What are the plates involved in the Galapagos triple junction?
Cocos Plate, the Nazca Plate, and the Pacific Plate
Define the term magnetic (dip) poles.
The two points on the Earth’s surface at which the magnetic field is vertical and has no horizontal component.
Any changes in the solar wind, and hence in the magnetic field, can allow these charged particles
to enter the upper atmosphere, causing:
Northern Lights - Aurora Borealis
Southern Lights - Aurora Australis
Describe the term Eötvös correction.
Correction applied to gravity data taken on moving vehicles.
In aeromagnetic surveys, aircrafts can use a fixed “stinger” (aircrafts tail) in order to?
Compensate for the aircraft’s magnetic field
What is space weather?
Space weather involves active processes and interactions between the magnetosphere and solar wind.
