# What happens when too much pressure builds up at a fault?

## What happens when too much pressure builds up at a fault?

An earthquake is caused by a sudden slip on a fault. When too much pressure builds, massive chunks of the Earth move and release intense energy. This results in waves that travel through the Earth’s outer crust to cause the shaking during an earthquake.

## What are the 3 fault types?

There are three main types of fault which can cause earthquakes: normal, reverse (thrust) and strike-slip. Figure 1 shows the types of faults that can cause earthquakes.

What is inactive fault?

Inactive faults are structures that we can identify, but which do no have earthquakes. As you can imagine, because of the complexity of earthquake activity, judging a fault to be inactive can be tricky, but often we can measure the last time substantial offset occurred across a fault.

What is the movement of a strike-slip fault?

Strike-slip faults are vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally. If the block opposite an observer looking across the fault moves to the right, the slip style is termed right lateral; if the block moves to the left, the motion is termed left lateral.

### Where does the fault begin to slip?

The rupture begins at a point on the fault plane called the hypocenter, a point usually deep down on the fault. The epicenter is the point on the surface directly above the hypocenter. The rupture keeps spreading until something stops it (exactly how this happens is a hot research topic in seismology).

### What magnitude will the big one be?

The ‘Big One’ is a hypothetical earthquake of magnitude ~8 or greater that is expected to happen along the SAF. Such a quake will produce devastation to human civilization within about 50-100 miles of the SAF quake zone, especially in urban areas like Palm Springs, Los Angeles and San Francisco.

What are the 4 major 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.

How can you identify a fault?

To correctly identify a fault, you must first figure out which block is the footwall and which is the hanging wall. Then you determine the relative motion between the hanging wall and footwall. Every fault tilted from the vertical has a hanging wall and footwall.

## Can an inactive fault become active again?

Inactive faults can become active again. In our case there are no signs of that, although UP seismologists remain observant. This diagram shows an earthquake along a fault. The focus of the earthquake is where the energy is released underground.

## What are 4 types of faults?

Where are strike-slip faults located?

Strike-slip faults are widespread, and many are found at the boundary between obliquely converging oceanic and continental tectonic plates.

How do you know if you have a strike-slip fault?

If you look across a fault zone and it looks like the rivers and valley on the other side have moved horizontally to the right the fault is a right-lateral strike-slip fault. If the land moves to the left it is a left-lateral strike slip fault.

### What will most likely happen every time a fault slips?

What will most likely happen every time a fault slips? The rocks will be stuck together.

### What are the 4 types of faults?

How far inland will the Cascadia earthquake reach?

The shaking will be felt for hundreds of miles – from the coast all the way inland to Boise, Idaho, even to the southeast toward Sacramento in California. As one section of the sea floor drops, so will the ocean water above it creating a massive tsunami that will inundate low-lying coastal communities.

How do you identify fault types?

Earth scientists use the angle of the fault with respect to the surface (known as the dip) and the direction of slip along the fault to classify faults. Faults which move along the direction of the dip plane are dip-slip faults and described as either normal or reverse (thrust), depending on their motion.

## What is a normal fault?

Normal Faults: This is the most common type of fault. It forms when rock above an inclined fracture plane moves downward, sliding along the rock on the other side of the fracture. Normal faults are often found along divergent plate boundaries, such as under the ocean where new crust is forming.