Liquefaction:

The process in which a granular solid (soil) takes on the characteristics of a liquid as a result of an increase in pore pressure and a reduction in stress. In other words, solid ground loses cohesion and starts flowing like a liquid.

Lithology:

Physical character of rocks.

Lithosphere:

The outer, rigid shell of the Earth above the asthenosphere. It contains the crust, continents, and plates.

Lg Wave:

A surface wave which travels through the continental crust. This wave type is the one which causes damage during large Eastern Canadian earthquakes.

Longitude:

The location of a point east or west of the prime meridian. Longitude is shown on a map or globe as north-south lines left and right of the prime meridian, which passes through Greenwich, England.

Love wave:

A major type of surface wave having a horizontal motion that is shear or transverse to the direction of propagation (travel). It is named after A.E.H. Love, the English mathematician who discovered it.

Low-velocity zone:

Any layer in the Earth in which seismic wave velocities are lower than in the layers above and below.

Magnitude:

Magnitude is a measure of the amount of energy released during an earthquake. It may be expressed using the Richter scale. See: What is the "magnitude" of an earthquake? What it is the difference between magnitudes ML and mN? Certain earthquakes have a negative magnitude, is this an error? Is there a maximum magnitude for an earthquake? At what magnitude do earthquakes begin to be felt? When does damage start do to be observed? Do several magnitude scales exist?

Mainshock:

The largest earthquake in a "cluster" of earthquakes. Mainshocks are sometimes preceded by "foreshocks", and generally followed by aftershocks.

Major Earthquake:

An earthquake having a magnitude of 7 to 7.99 on the Richter scale.

Mantle (of Earth):

The main bulk of the Earth, between the crust and the core, ranging from depths of about 40 to 3470 kilometres. It is composed of dense silicate rocks and divided into a number of concentric shells. Under Eastern Canada, it can be found at around 40 km depth.

Meizoseismal region:

The area of strong shaking and significant damage in an earthquake.