EAS 220 Lab 3: EARTHQUAKES

Travel Time Graph

Plate Boundaries

Types of Boundaries Divergent Convergent Transform

Divergent Boundaries: Spreading zones (ex. Mid Atlantic Ridge, Red Sea Rift)

Convergent: Subduction (ex. West coast of South America, Aleutian Islands)

Transform Boundaries: Plates slide past each other (ex. San Andreas in California)

Richter MagnitudesDescriptionEarthquake EffectsFrequency of Occurrence Less than 2.0Micro Microearthquakes, not felt. About 8,000 per day Minor Generally not felt, but recorded. About 1,000 per day Minor Often felt, but rarely causes damage. 49,000 per year (est.) Light Noticeable shaking of indoor items, rattling noises. Significant damage unlikely. 6,200 per year (est.) Moderate Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings. 800 per year Strong Can be destructive in areas up to about 100 miles across in populated areas. 120 per year Major Can cause serious damage over larger areas. 18 per year Great Can cause serious damage in areas several hundred miles across. 1 per year Great Devastating in areas several thousand miles across. 1 per 20 years 10.0+Great Never recorded; see below for equivalent seismic energy yield. Extremely rare (Unknown)

Earthquake Facts Largest ever recorded: 9.6 in Chile in nd largest: (Largest US Earthquake): Alaska 1964 Good Friday Earthquake, Magnitude rd largest: Indian Ocean Indonesia/Sumatra. Generated tsunami ( )

*3 big earthquakes: 1811, 1812 (within two months!) *made Mississippi flow backwards *Rang church bells in Boston and felt widespread. Probably close to 7.8 magnitude. New Madrid Fault Zone

Biggest NY Earthquakes Utica, Attica, Syracuse have had quakes. Massena 1940’s: magnitude 6. Blue Mountains: active area, magnitude 5.5 a few years ago. Historically, large earthquakes in NYC area. Frequent magnitude 2-3. Beneath city itself, historically 6’s. Magnitude 5.1, 2002.