Earthquake magnitude scales: Earthquakes are commonly measured using the Richter scale based upon the magnitude of surface seismic waves, Ms, at a period of 20 seconds. The Richter scale is so recognized that it is commonly used to describe the size of tsunamigenic earthquakes. Earthquake-generated tsunamis are associated with seismic events registering more than 6.5 on the Richter scale. Unfortunately, the Ms scales saturates around a magnitude of 8, precisely at the point where significant tsunami begin to form. A better measure of the size of an earthquake is its seismic moment, Mo, measured in Newton meters (N m). The seismic moment has a similar scaling to the better-known Richter scale, but has the advantage of growing with earthquake size, rather than saturating when it reaches a value around 8.0.

Fjords: (in old Norse “Fjörthr”) sea entering or narrow bay that is inland between rocky and steep walls. The walls of a fjord continue below the surface of the water. Normally they are less deep near the exit and deeper in the interior.
Most of the fjords of the world are located along the coast of Norway. Sognafjorden is the longest and is 204 Km. inland and has a depth of more than 1.308 meters. Other places that you can find fjords are the coasts of British Columbia, Alaska, Island, Greenland, New Scotland, Maine, the south of Argentina, Chile y New Zeeland.

Pyroclastic flows: Pyroclastic flows are high-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds. This phenomenon is very dangerous because of its high temperature and speed and because of its great extension covered. Temperatures are between 350°C to 1000°C, its velocities are 50 to 250 km/h and the affected areas are between 10 to 600 km2 . The pyroclastic flows are considered the most lethal phenomenon, being the possibilities to survive almost impossible.

Ring of Fire: A zone of frequent earthquakes and volcanic eruptions

Seismic waves: Earthquakes are shock waves transmitted through the Earth from an epicenter that can lie as deep as 700 km beneath the Earth’s crust. These seismic waves consist of four types: P, S, Rayleigh, and Love waves. P waves are primary waves that arrive first at seismograph. S or shear waves behave very much like the propagation of a wave down a skipping rope that has been shaken up and down. These waves travel 0.6 times slower than primary waves. The spatial distribution and time separation between the arrival of P and S waves at a seismograph station can be used to determine the location and intensity of an earthquake. Love and Rayleigh waves spread slowly outwards from the epicenter along the surface of the Earth’s crust. Love waves have horizontal motion and are responsible for much of the damage witnessed during earthquakes. Earthquakes that generate tsunami also obtain their energy from Rayleigh waves.

Subduction zones: where two plates converge and one is thrust under the other, descending into the mantle. Where an oceanic plate collides with a continental plate, the oceanic plate tips down and slides beneath the continental plate forming a deep ocean trench (long, narrow, deep basin)

Tectonic Plates: The earth's surface is broken into nine large and many small moving plates. Six of the large ones are named for the continents embedded in them: the North American, South American, Eurasian, African, Indo-Australian, and Antarctic, the other three are oceanic plates: the Pacific, Nazca, and Cocos, These plates, each about 50 miles thick, move relative to one another an average of a few inches a year.

Run-up: indicates the vertical wave elevation along the shore or the maximum half-height of the wave recorded on a tide gage.