Earthquakes are the violent shaking of the earth in response to the movement of tectonic plates.

Tectonic plates are the large pieces of crust that move around the earth These plates come in two forms: Continental and Oceanic

Continental crust is made of less dense rock, and “floats” higher of the mantle, or magma under the crust When it collides with oceanic crust, the denser oceanic crust sinks underneath the lighter continental crust; This is called subduction

Plates move by a process called convection Hot magma rises from the crust and pushes the plates As the magma cools, it drifts back down to the core, where it is heated again

Faults are cracks in the earth that indicate where earthquakes have occurred There are 3 kinds of faults – Normal – Reverse – Slip The kind we are most concerned with is the Normal Fault

Even though Utah is located in the center of a tectonic plate, it is still affected by earthquakes Every year, there are about 700 earthquakes in Utah – Most of these earthquake only measure on the Richter scale, so we cannot feel them

The major fault in Utah is called the Wasatch fault, and is located along the front of the Wasatch Range.

The Wasatch fault has experienced several large earthquakes over the last 2000 years; the last big quake occurred in about 1600 A.D. These large quakes occur about every 350 years

Geologists have determined that the Wasatch fault is overdue for a large earthquake by about 200 years. They anticipate this quake reaching magnitude Scientists predict that there is a 25% chance that an earthquake of this size will occur in the next 100 years.

It is not possible to predict earthquakes, but we know that an earthquake will happen in Utah While we don’t know exactly when it will happen, we can be ready by preparing now

It is not possible to predict earthquakes, but we know that an earthquake will happen in Utah While we don’t know exactly when it will happen, we can be ready by preparing now

Preparation for an earthquake can prevent many of the problems that may occur commonly during and after earthquakes

Preparation for an earthquake should include the following steps: 1. Secure anything around your house that could fall because of shaking: Lights, cabinets, bookcases, dishes and other breakable objects. 2. Know where to find your house’s fuse box and gas line, and learn how to turn them off: Most casualties in an earthquake occur because of fires after the quake. Knowing where these things are and how to turn them off could save lives.

3. Make a family plan: Discuss with your family what to do if an earthquake strikes at home, work, or school. Plan a central meeting point and emergency contacts in case someone is hurt or lost. Hold drills with your family so you are ready when you need to act. 4. Store food, water, and other emergency supplies: In the event of a big earthquake, stores may shut down, roads may be impossible to drive on, and emergency services may be unavailable. Having food, water, clothes, and a way to stay warm is critical to your emergency plan.

When an earthquake does strike, it is important to act fast and take measures to ensure your safety. First, find cover!

The best things to hide under are strong, sturdy pieces of furniture: Tables, desks, etc. DO NOT STAND UNDER A DOOR FRAME! Despite what you have heard, they are not the safest place to hide.

Once the shaking stops, check around you to makes sure you and everyone else is safe and unharmed. If you are home, go shut off the electricity and gas as soon as you can.

IMPORTANT: You should NOT use your phone immediately after an earthquake UNLESS someone is seriously injured or dying. If too many people use their phones, it could overload phone lines and cell phone towers, preventing important calls from getting through.

Take safety precautions when traveling after an earthquake – Wear sturdy shoes and warm clothes – Avoid fallen buildings, power lines, etc. – Use flashlights to see; matches could cause an explosion if there is a gas leak – Don’t try to travel far and avoid busy areas; people will be panicked and there will probably be a lot of chaos.

AFTERSHOCKS After any big earthquake, there will be minor tremors called aftershocks. These can be as big as the main earthquake, so use extreme caution even after the shaking stops.

There are other hazards that could cause damage or physical harm after the earthquake stops Floods Fires Avalanches Mud and Rockslides

Liquefaction is also possible following an earthquake. Liquefaction occurs when water and dirt are shaken together during a violent earthquake – This causes the soil to behave like a liquid; buildings and roads can be damaged or sink into the liquefacted soil

Here in Utah, liquefaction will occur, but only in certain areas. – Provo, Sandy, and Salt Lake will experience liquefaction – Alpine will NOT experience Liquefaction, but will probably have mud and rockslides