earthquakes Flashcards
ring of fire
The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. Roughly 90% of all earthquakes occur along the Ring of Fire, and the ring is dotted with 75% of all active volcanoes on Earth
Strike-slip fault
Strike-slip tectonics or wrench tectonics is the type of tectonics that is dominated by lateral movements within the Earth’s crust. Where a zone of strike-slip tectonics forms the boundary between two tectonic plates, this is known as a transform or conservative plate boundary
Normal fault
Normal Fault: In the field of geology, a normal fault is a type of dip-slip fault where the hanging wall moves downwards from the footwall. The average dipping angle of a normal fault ranges from 45 to 90 degrees. Normal faults are the opposite of reverse faults.
Reverse fault
In a reverse fault, the block above the fault moves up relative to the block below the fault. This fault motion is caused by compressional forces and results in shortening. A reverse fault is called a thrust fault if the dip of the fault plane is small.
P-waves
P waves, or Primary waves, are the first waves to arrive at a seismograph. P waves are the fastest seismic waves and can move through solid, liquid, or gas. They leave behind a trail of compressions and rarefactions on the medium they move through. P waves are also called pressure waves for this reason.
S-waves
S-waves. S-waves, also known as secondary waves, shear waves or shaking waves, are transverse waves that travel slower than P-waves. In this case, particle motion is perpendicular to the direction of wave propagation
epicenter
the part of the earth’s surface directly above the focus of an earthquake
focus
The focus is the place inside Earth’s crust where an earthquake originates. The point on the Earth’s surface directly above the focus is the epicenter. When energy is released at the focus, seismic waves travel outward from that point in all directions
Richter magnitude scale
is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 paper, where he called it the “magnitude scale
explosive volcano
n volcanology, an explosive eruption is a volcanic eruption of the most violent type
nonexplosive volcano
Non-explosive eruption of lava appears to result from rapid, sub-surface gas release from magma ascending as a permeable foam. The degassed foam then collapses during extrusion. Conditions of shallow ascent, rather than pre-eruption volatile concentrations, control eruptive behaviour
Krakatoa
Krakatoa, also transcribed Krakatau, is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group comprising four islands.
Yellowstone supervolcano
The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of Wyoming.
San Andreas fault
The San Andreas Fault is a continental transform fault that extends roughly 1,200 kilometers through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip.
Mid-Oceanic Ridge
A mid-ocean ridge is a seafloor mountain system formed by plate tectonics. It typically has a depth of about 2,600 meters and rises about 2,000 meters above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary.
