Readings for Homework Flashcards
How is the speed of the inner core calculated?
he BC-DF measurements are used to find the minimum bound for the rotation rate. In this paper the BC-DF data from COL was used to find this minimum. These numbers were then compared at the various stations. This data must be collected over many years.
How does the rotation of the outer core relate to the earth’s magnetic field?
The rotation of the inner core with respect to the outer core causes heat fluctuations. The heat flux drives the convection currents of the outer core responsible for Earth’s magnetic field.
What is the key feature of the inner core that makes it possible to measure it’s rotation
It is anisotropic. In this instance the anisotropy is believed to be due to the preferred orientation of iron mineral crystals.
How does the movement of the mendencino Triple Junction affect the thickness of the crust?
The crust is thinner before and after the triple junction, and thickest at the triple junction. After the passing thinning is caused by extension. The coupling of the North American plate with the Gorda slab, transports crustal material and cause thickening.
Why is there an age offset across a fracture zone?
There is an age offset because there are ridges on both sides of the fracture zone where new material is created, which causes a movement of the plates with time. The younger seafloor is hotter and subsides faster.
What does the locked fault model represent?
A locked fault occurs when a fracture zone is formed by plates that do not change direction, and the formed fracture zone is strong enough to withstand the stresses of the area.
