TechtonicPlates25 | Artpod 2021

TECHTONIC PLATES

Three types of Techtonic Plate Movement:

1. Divergent

Plates move apart

2. Convergent

Plates move together, colliding to form mountains, OR

Subduction where one slides under another

3. Transform

plates slide past each other horizontally.

Techtonic Plates are large moving sections of the Earth's Crust and Upper Mantle sitting on molten liquid rock below. Over millions of years they create the continents, and their techtonic movement create events like volcanic Activity and Earthquakes.

Numbers of plates:

There are many models since 1968 - current.

Most commonly used is Byrd Model (2003) of 52 plates.

(Other models range in number from 8 to 97, often sighting "micro-plates" to explain Earthquakes occuring outside a known plate boundary.

Most earthquakes occur along faults at the boundaries of tectonic plates

The Alpide Belt (Alpine-Himalayan seismic belt) is a major seismic belt and mountain chain that stretches from the Azores, through the Mediterranean and Middle East, to the Himalayas and Indonesia, where it connects with the Pacific Ring of Fire (Circum-Pacific Belt). It is the world's second most seismically active region and is responsible for approximately 17% of the planet's largest earthquakes, following the Pacific Ring of Fire

Pacific Ring of Fire

Earthquakes and Volcanic Eruptions

frequently occur at these Plate Boundaries

Most earthquakes occur along faults at the boundaries of tectonic plates

CALIFORNIA IS ON THE RING OF FIRE

The San Francisco Bay Area has several major Active Fault Lines

MAJOR FAULTS

SF BAY AREA:

San Andreas

Hayward

Calavaras

Rodgers Creek

Greenville

HAYWARD FAULT

Sept. 22, 2025 ~4.3m, 3am, Berkley, CA

Last Large Earthquake ~7.0m, Oct, 21, 1868

SAN ANDREAS FAULT

CALAVERAS FAULT

RODGERS CREEK FAULT

GREENVILLE FAULT

EARTHQUAKE EARLY WARNING SYSTEMS
SAFETY

SHAKE ALERT Early Warning (EEW)

https://www.shakealert.org/

An earthquake early warning system on the west coast of the United States could provide up to tens of seconds of warning prior to shaking arriving. The time required to detect and issue a warning for an earthquake is dependent on several factors:

The ShakeAlert® Earthquake Early Warning (EEW) System, managed by the U.S. Geological Survey, detects significant earthquakes quickly enough so that alerts can be delivered to people and automated systems potentially seconds before strong shaking arrives. ShakeAlert is the nation’s only public EEW system and it serves over 50 million residents and visitors in California, Oregon, and Washington. The purpose of the ShakeAlert System is to reduce the impact of earthquakes to save lives and property.

Earthquake Early Warning systems are operational in several countries around the world, including Mexico, Japan, Turkey, Romania, China, Italy, and Taiwan. All of these systems rapidly detect earthquakes and track their evolution to provide warnings of pending ground shaking. Systems can vary depending on the local faults and the specific ground motion data available.

When you receive an earthquake early warning or feel the first tremors, the safest action is to Drop, Cover, and Hold On immediately. Drop to the ground, take cover under a sturdy table or desk, and hold on until shaking stops. Stay away from windows, hanging objects, and outer walls. Remember that doorways are not safer than other parts of a building.

If you're caught in an earthquake and have no furniture to shelter under, you should drop to your hands and knees, cover your head and neck with your arms and hands, and crawl next to an interior wall to wait for the shaking to stop. This position keeps you stable and makes you a smaller target for falling debris