An american geologist

When was seafloor spreading theory proposed

Coined the term "seafloor spreading"

New oceanic crust is formed at mid ocean ridges and spreads outwards, pushing older crust away from the ridge.

A deep canal in the ocean floor

meaning of SONAR

Uses longitudinal waves to find and identify objects in the water

Region between an oceanic trench and the associated volcanic arc found in convergent margins

A.K.A destructive plate boundary

It occurs when two plates push against each other

areas where tectonic plates dive beneath other plates into earth's interior

100km before subducting plate heats up

Two seismologist

Three Convergent Boundaries

Sierra madre mountain range, Andes Mountains and Cascade Range

Trenches, The arc of volcanic islands

Zone of kountains - The himalayas

A.K.A constructive plate boundary

It occurs when two plates move apart from each other

This plate is characterized by tensional stresses that normally produce long rift zones, normal daults, and basaltic volcanism

A.K.A conservative plate boundary

Two plates slide horizontally past one another

These are generally vertical and prallel to the direction of movement. They are produced by sharing and are closely related to Divergent plate boundaries on the ocean floor

Pccur in the ocean floor

When on land