ERTH 374: Science of Natural Disasters in Popular Culture - Earth Structure & Silicates

Vocabulary flashcards focusing on Earth's formation, seismic investigation methods, interior chemical and physical boundaries, silicate structure, and lithospheric movement mechanisms.

Solar Nebula Theory

The theory explaining that Earth formed about $4.6\text{ billion}$ years ago.

Protoearth

The protoplanet (planetesimal) that represented Earth during its early stage of formation.

Seismic Investigation

An artificial investigation method that allows the deepest probing into Earth's interior, mostly down to $5\text{ to }7\,\text{km}$ and rarely down to $30\text{ to }40\,\text{km}$.

Seismic Reflection Diagram

A methodology where detonation produces incident waves ($I$) that result in refracted waves ($r1$ to $r3$) and reflected waves ($R0$ to $R3$) measured by geophones ($g1$ to $g6$) at subsurface discontinuities.

Seismic Marker

A visual reflection line in seismic subsurface profile data that documents a discontinuity in the Earth subsurface.

Epicentre

The point on the Earth's surface located directly above the hypocentre (focus) of an earthquake.

Hypocentre (Focus)

The actual position at depth within the Earth where energy discharge originates during an earthquake.

Mohorovichich Discontinuity

The chemical composition boundary that separates the Earth's crust from the underlying mantle.

Guttenberg Discontinuity

The chemical boundary that divides the Earth's mantle from the core.

Silica Tetrahedra

The basic building block of silicate minerals, consisting of a central silicon ion ($\text{Si}^{4+}$) covalently bonded to four oxygen ions ($\text{O}^{2-}$).

Tight Packing

A structural model closer to reality in silicate minerals where oxygen and silicon ions directly touch one another.

Silicates

The dominant group of minerals found in Earth's crust, exemplified by minerals like Olivine and Quartz.

Iron Meteorite (Vulcan, AB)

An exterior sample of a metallic meteorite composed predominantly of iron.

Iron Meteorite (Xiquipileo)

A cut section of an iron meteorite revealing internal crystalline structures.

Physical Layers of Earth

The classification of Earth's interior based on physical properties, divided into lithosphere, asthenosphere, mesosphere, outer core, and inner core.

Lithospheric Movement

Tectonic motion driven by heat sources deep within the Earth, creating convection currents across the mantle, asthenosphere, oceanic trenches, and oceanic ridges.