What did the focal mechanism tell about the cause of this earthquake?

A focal mechanism, or “beachball”, is a graphic symbol that indicates the type of slip that occurs during an earthquake: strike-slip, normal, thrust (reverse), or some combination. It also shows the orientation of the fault that slipped.

How do you plot focal mechanisms?

Plot single focal mechanism by clicking button on map toolbar, and then double clicking on the earthquake location on the map. This will plot on the map, and you can drag it to the location where you want it.

Which nodal plane is the fault plane?

Normal Faults and Thrust Faults By studying the geology one can determine that the left-most nodal plane is the fault plane for both the normal and the thrust faults.

What is a fault plane solution?

A fault plane solution is a way of showing the fault and the direction of slip on it from an earthquake, using circles with two intersecting curves that look like beach balls. Also called a focal-mechanism solution.

What are moment tensors?

A mathematical representation of the movement on a fault during an earthquake, comprising of nine generalized couples, or nine sets of two vectors. It is often represented with “beach balls” just like the focal mechanism (or fault plane solution). See also seismic moment and fault plane solution.

What is focal mechanism solution?

fault-plane solution A fault plane solution is a way of showing the fault and the direction of slip on it from an earthquake, using circles with two intersecting curves that look like beach balls. Also called a focal-mechanism solution.

How do you determine fault orientation?

Strike. The strike is an angle used to specify the orientation of the fault and measured clockwise from north. For example, a strike of 0° or 180° indicates a fault that is oriented in a north-south direction, 90° or 270° indicates east-west oriented structure.

What are the 4 types of faults?

There are four types of faulting — normal, reverse, strike-slip, and oblique. A normal fault is one in which the rocks above the fault plane, or hanging wall, move down relative to the rocks below the fault plane, or footwall. A reverse fault is one in which the hanging wall moves up relative to the footwall.

Is a normal fault vertical or horizontal?

Normal dip-slip faults are produced by vertical compression as Earth’s crust lengthens. The hanging wall slides down relative to the footwall. Normal faults are common; they bound many of the mountain ranges of the world and many of the rift valleys found along spreading margins of tectonic plates.

How do you know if a plane is at fault?

What is a moment tensor earthquake?

moment tensor A mathematical representation of the movement on a fault during an earthquake, comprising of nine generalized couples, or nine sets of two vectors. It is often represented with “beach balls” just like the focal mechanism (or fault plane solution). See also seismic moment and fault plane solution.

What are focal plane arrays ( FPAs ) used for?

SBF develops and manufactures focal plane arrays (FPAs) that deliver high-resolution imagery in real-time, integrated dewar cooler assemblies for high-performance sensors, and camera cores that offer big-sensor performance in compact and low-SWAP configurations. SBF offers a diverse selection of off-the-shelf and custom-built FPAs.

How can I prepare a focal mechanism solution?

There are several programs available to prepare Focal Mechanism Solutions (FMS). BBC, a MATLAB -based tool box, is available to prepare the beach ball diagrams. This software plots the first motion polarity data arrived at different stations. The compression and dilation are separated using mouse help.

Where are the focal plane arrays at Lockheed Martin?

At Santa Barbara Focalplane (SBF), Lockheed Martin’s infrared (IR) center of excellence, seeing is believing.

Where are the nodal planes in the focal mechanism?

If there are sufficient observations, one may draw two well-constrained orthogonal great circles that divide the compressive from the tensional observations and these are the nodal planes. Observations from stations with no clear first motion normally lie close to these planes.