Tsunamis. Seismic Sea Waves. Triggers / Cause (4) Speed, height, period, wavelength Trough often arrives first

Transcription

1 Seismic Sea Waves Triggers / Cause (4) Speed, height, period, wavelength Trough often arrives first Tsunamis Tsunamis 15 min Volcanoes 5 min Mass Wasting 10 min Fig , p. 321 Historical Tsunami Events and Resulting Fatalities 230, Indian Ocean earthquake with tsunami 12/26/ , Lisbon earthquake, tsunami, earthquake and fire, Portugal and Morocco 100,000 - Awa, Japan, ,000 - Messina, Italy, earthquake and tsunami, ,000 - South China Sea, 1782, including deaths in Taiwan 36,000 - Krakatoa volcano explosion, ,000 - Tokaido-Nankaido, Japan, ,000 - Japan, ,674 - Chile, ,070 - Sanriku, Japan, ,850 Japan, 3/11/11 (~3,287 missing) 15,030 - Southwest Kyushu, Japan, ,486 - Ryukyu Trench, ,233 - Tokaido-Kashima, Japan, ,000 - Nankaido, Japan, ,000 - Moro Gulf, Philippines, ,000 - Papua New Guinea, ,008 - Sanriku, Japan, ,000 - Chilean Earthquake, deaths in Chile, U.S. (Hawaii), Philipines and Japan Aleutian Island earthquake, deaths in Hawaii and Alaska, U.S., Good Friday Earthquake, Alaska and Hawaii, U.S., 1964 Japan Earthquake Tsunami Seacliff State Beach, Aptos, CA 3/11/11 1

2 Reducing Tsunami Hazards? Warning system in all major oceans Better Land Use Planning Local gov t evacuation routes and procedures Education about warning signs Ground-shaking in coastal areas Unusual disturbance of ocean, drop in SL Move to high ground (several hours-days) First wave generally not largest Volcanoes Volcanoes: landforms created when magma escapes from Earth s interior through vents or Earth s surface and becomes lava. Lava cools and solidifies around vents forming volcanic rock. Globally, ~50 volcanoes erupt each year. Located at both convergent and divergent plate boundaries (not transform) and interior plate hot spots. 2

3 Hazards Volcanic materials burry and destroy habitats and property; toxic gases (acid rain) Ash clouds can block sun and lower global temperature Lahars (volcanic mudflows formed from sudden ice melting) Tsunamis html Volcanism Benefits Release of gases and water vapor forming atmosphere and hydrosphere Addition of fertile soils Addition of real estate (Hawaii, Pacific Islands, Iceland) Geothermal energy Info about Earth s interior Reducing Volcanic Hazards? Map high risk areas Volcanic zoning (no development in volcanically prone areas) Better prediction (monitor volcano s surface, temperature, gas release, seismic activity) Effective evacuation plans Successful case histories: Mount Pinatubo Philippians, Mount St Helens, Oregon brave-boiling-waters-capture-drama-searing-hot-lava-crashing-seas- Hawaii.html Main Causes: Water, Seismic Activity, Volcanoes, Humans: Slumps / Slides Mudflows, Earthflows Rock Falls Lahars (volcanic) Debris Flows Avalanche 08/la-conchita-landslide-verdict.html Southern Italy Landslide 2/16/10 Mass Movement 120 m wide, 330 m long, and >30 m deep, with an estimated volume of 1.3 million cubic meters. La Conchita

4 La Conchita 1/10/05 Irrigation Water leakage: septic tanks other utilities Surface water diversion Road construction Mining operations Logging Fires Excavation of slope Mass Movement Triggered by human activities Mass Movement Santa Cruz Mountains especially susceptible Topography Geology (Dip Slopes) Rocks: soft fractured, folded, faulted Rainfall, El Niño winters Earthquakes Wildfires SOLUTIONS? 4

5 California rainstorms Earthquake events 10/17/89 The Hawaiian Islands: a combination of volcanism, slope failure and megatsunamis 5

6 The Great Crack is an eight-mile-long, 60 feet (18 m) wide and 60 feet (18 m) deep fissure in the island Cape Verdean island of Fogo 73,000 yrs BP volcano collapse Creates waves 240 m or 800ft 6

7 Coastal Erosion / Flooding / Rising Sea Level Storms Waves Coastal slides Human activities Sea Level Measurements from San Francisco Hurricane Katrina 8/29/05 Earthobservatory.nasa.gov 7

8 New Orleans Flooding Human impacts on coastal erosion: Santa Cruz Harbor example Earthobservatory.nasa.gov californiacoastline.org Coastal Armoring; seawalls, rip-rap, and more Coastal Armoring; seawalls, rip rap and more californiacoastline.org californiacoastline.org 8

9 Reducing Coastal Erosion Hazards How will sea level rise impact coastal erosion? Establish better land-use planning Monitor erosion rates Map high risk areas Limit coastal armoring and damming of rivers Evaluate and monitor coastal engineering projects Better land use planning californiacoastline.org Better land use planning Rio Del Mar, Aptos Ca Geologic Processes and Hazards Definition of Geology External and Internal Processes: examples of each Fundamentals of Plate Tectonics: definition, types of boundaries, general geography, hazards & resources Earthquakes: focus, epicenter, types of waves, measuring strength & location, outcomes, damage a function of, prediction Tsunamis: shallow water waves, Japan Earthquake Volcanoes: definition, location, hazards, benefits, prediction Mass Wasting: causes, different types, susceptibility, human influence californiacoastline.org Coastal Erosion / Flooding: sea level rise, storms, land use planning 9

10 Geologic Processes create: Hazards and Resources Hazards (dangerous events and conditions) Resources (the materials we use to get the things we want: fuel our cars, power our homes, computers, construct homes, buildings, roads etc.) Links between internal and external geologic processes: internal processes create new crust, cause hazards, concentrate minerals. external processes carve up crust creating landforms and environments which are subjected to hazards (flooding, landslides), concentrate minerals. 10