Earth Science tradition Focuses on processes that create environments significant to humans. - How have Earth components been formed? - How do they change; what is likely to bring about future changes? - How are environmental features related to past, present, future human use of Earth? Earth forces Tectonic forces. Gradational processes. Plate tectonics Accounts for continental drift, seafloor spreading, movement of lithospheric plates, and deformation of Earth’s crust. Subduction Plates with different types of crust push against each other, denser oceanic crust is forced down into the asthenosphere. December 26, 2004 Location map of Indonesia from the National Earthquake Information Center (http://neic.usgs.gov/neis/bulletin/neic_slav_l.html) Earthquake caused by subduction of Indian plate beneath the Burma microplate. Relative motion of Indian plate to Burma microplate = 0.06 m per year (2.4 inches per year). Tectonic Setting of Earthquake of 26 December 2004 from United States Geological Survey (http://earthquake.usgs.gov/eqinthenews/2004/usslav/) Areas potentially affected by tsunami inundation and run- up in yellow (i.e. shore zones < 20 m above sea-level) Areas Potentially Affected by Tsunami of 26 December 2004 from UNOSAT (www.unosat.org) Predicted Arrival Time of First Tsunami Wave (in hours after earthquake) Countries Reporting Casualties from Earthquake and Tsunami Indonesia Thailand Andaman Islands (India) Nicobar Islands (India) Myanmar Bangladesh India Sri Lanka The Maldives The Seychelles Kenya Somalia Tanzania In addition, many western nations reported fatalities and missing among tourists who were visiting the affected countries. Events known to generate tsunamis Submarine earthquakes Explosive volcanic eruptions Submarine landslides Terrestrial landslides that enter water Impacts of large extraterrestrial objects (e.g. asteroids or comets) in the ocean. Other earthquake-generated tsunamis Great Chilean quake and tsunami, 1960 (largest quake ever recorded, 9.5), devastated Pacific Rim. Good Friday quake, Anchorage, Alaska, 1964 (9.2) devastated coastal Alaska and Crescent City, California. Krakatau, August 1883 Triggered by explosive volcanic eruption. Among most violent eruptions in last 200 years. Destroyed 165 coastal Indonesian villages on Java and Sumatra – approx. 36,000 fatalities. Prior to December 2004, most destructive tsunami on record. Earthquake prediction Property value changes. Reduced availability of insurance, mortgages, investment. Temporary/permanent population relocation. Decline in employment. Reduction in public services. Earth materials Vary as to mineral composition: - igneous - sedimentary - metamorphic Rocks as constituent ingredients of landforms Strength, permeability, chemical content control how rocks respond to: - tectonic forces building landforms, - gradational processes wearing landforms away.