Introduction to EARTH SCIENCE
Course Information
Resources Textbook: Tarbuck, E.J., Lutgens, F.K., Tsujita, C.J., and Hicock, S.R., 2015. Earth: An introduction to physical geology, 4th Canadian edition. Pearson, Toronto, 552 pp. Course website: facultyweb.kpu.ca/~jkoch/geog1120.htm
ME!: in class OR during office hours Office: Fir 342 Email:
[email protected]
Yours truely Research interests are climate change and glacier history. Have taught numerous courses, including this one, before. Worked on an icebreaker as staff geologist along the westcoast of South America, in Antarctica, and the North Atlantic. Want to make this your course, so I listen to constructive criticism and suggestions. Everything’s possible, but cheating and plagiarism are where the fun ends! I try to be laid-back, but you will have to do the work to get a good grade!
What do you expect? Why did you sign up for this course? What do you want to learn? Have you background in geology/geography? To make my life easier, I’d like each of you to come to my office and introduce yourself during office hours.
Course Information
Earth Science Log •
Throughout the semester (Sept 6 - Dec 5, 2016), students will be asked to collect information about earth science that is reported in the news. The log should include stories related to earth science as covered in class (e.g., new research findings, air pollution, climate change, etc.). You should probably have one entry per week, and make it the top story of that week. For example, if an earthquake hits Chile and a volcano erupts in Indonesia in the same week, the only entry in your summary should be the one with the bigger impact. The typewritten log will be handed in the day of the last class(Dec 5), and should be submitted by email as electronic file.
Earth Science Log The final typewritten earth science log should include the following information: – Topic (earthquake, flood, hurricane, etc.) – Date (be specific; if there is a start and end date, list both; if there is a time, mention it) – Location (be specific; countries like ours are big, so a country name may not be a sufficient location) – Why was it reported in the news? (impact on ecology, economy, humans, etc.; provide specific information, such as total economic loss due to property damage, casualties; or for topics not related to hazards, think of events like climate change talks, policy decisions on tar sand exploration, etc.) – Sources of information (newspaper/magazine articles, television/radio reports, internet URLs; they need to be reliable, so someone’s twitter, blog, instagram, etc. should not be your source of information; be specific here, cbc.ca is not enough)
Earth Science Log Entries in the log should be in chronological order and part of the grade will be based on its organisation. Make the instructor's life easy...appearance does count! While teamwork is encouraged, the log must be yours, written in your own words. Logs that are exact copies will not be marked. Cutting and pasting information straight from the Web is not acceptable!!! Grading the Earth Science log In order to grade the logs, I will go through each log and identify all entries. Every entry will count if there was enough information for me to reasonably assume that the entry is valid, or if you provided a source that I can go to verify the information. Up to 70% will be awarded for selecting relevant events, up to 20% will be awarded for the description for each entry, and up to 10% for the presentation and appearance of your log.
Earthquake – What would you do? An earthquake along the Cascadia Subduction Zone (Mw=9.1) strikes at 7:30am on January 26, 2019. The shaking lasts for three minutes. Put yourself in the place of three of the characters (handout with different scenarios will be handed out before the assignment), and briefly describe their main questions and actions from 7:33-7:35am in a written short summary. We will then go through this in lab on Oct 31, and you can volunteer to present your summary .
Fieldtrip There is a mandatory, full-day fieldtrip on Saturday, Nov 19. We will leave at 10am and head to Point Grey and the shoreline around UBC to talk about coastal processes, hazards, etc. We will return sometime around 6pm. It will be a great experience to actually see what we will have talked about in class. If you cannot partake in this fieldtrip due to other obligations, please inform me within the first two weeks of the semester. There will be more information as we approach the date.
Overview
Basics of Earth Sciences • • •
Plate tectonics Rocks and minerals Geological time
Minerals: Building blocks of rocks •
Definition of a mineral: • Naturally occurring • Inorganic solid • Ordered internal molecular structure • Definite chemical composition
•
Definition of a rock: • A solid aggregate or mass of minerals. (The mineral grains are cemented or interlocked together.)
Igneous Rocks
Volcanic Rhyolite
Andesite
Basalt
Granite
Diorite
Gabbro
Plutonic
Sedimentary Rocks
Geological Time
Early Earth (4.6 – 4.0 billion years ago ) – Prisocoan Eon • Very hot – liquid rock for much of this time – magma oceans! • Heavy bombardment phases – many water-rich comets and iron-rich meteorites, including very large impacts probably
Proterozoic Earth (2.5 billion to 540 million years ago) • Still just bacterial life until about 700 million years, then more complex lifeforms evolve (though still softbodied, leave impressions only) • Ediacara fauna
Plate Tectonics
Subduction zones
Volcanism along subduction zones – Partial melting of ocean crust & overlying sediment – Water helps to lower melting temperature
– More silica rich than basalts • intermediate to felsic
Fissure Eruptions • •
•
Often extend radially from volcano centre Related to regional tectonics
Krafla volcano, Iceland
Earthquake terminology • • •
Focus (hypocentre) - source of the EQ on the fault Faults - fractures along which displacement occurs Epicentre - point on Earth’s surface directly above the focus
Weathering • • •
the set of exogenic (physical, chemical and biological) processes that alter the physical and chemical state of rocks at or near the earth's surface intensity of most weathering decreases with depth, because variations in temperature and moistures decrease with depth therefore biochemical weathering is generally confined to the uppermost few metres of soil and rock
Soil profiles and horizons •
• •
•
A cross section of the soil blanket between bedrock and atmosphere usually reveals a series of zones of different colors, chemical compositions, and physical properties A Horizon – Rock material is exposed to heavy leaching B Horizon – Zone of accumulation (zone of deposition) – Zone of leaching C Horizon – Very coarsely broken-up bedrock – Below this is R horizon: bedrock or parent rock material
Podzolization •
Soils and coniferous forest – Forms in humid-temperate climates – Coniferous forest surface litter is acidic – Removal of iron, aluminum, organic mater from A to B-horizon – Most soluble ions (Ca, Mg, Na) are leached in upper layer
Mass wasting: gravity at work
• 3 main factors: – Nature of slope – Amount of water – Steepness & instability of slope
Coasts •
Types and processes
Hurricanes
Sea-level change •
Recent trends
Floods of the Mississippi River system
Water as a resource
Ice & Glaciers
Glaciers
1978
Water as a resource
2000
Glaciers in the tropical Andes: La Paz - Zongo Glacier 75% of electric power from hydropower plants in the Zongo Valley During dry season (April - November [monthly precipitation: 10 - 40 mm) Zongo Glacier provides 50 to 120 l/s of water.
Natural hazards vs. Natural resources •
A geophysical process/event can be beneficial – a Natural resource
•
But at extreme levels ! Natural hazard ! Natural disaster
Physical element
e.g., rainfall
Damage threshold
flood
hazard resource
Tolerance band
drought
hazard
time e.g., avg. rainfall vs flood; snowfall vs blizzard; winds vs hurricane
Sensitivity trends
•
• •
Worldwide sensitivity is increasing: – Increased vulnerability • increasing population in vulnerable areas • increasing urbanisation and growth of Megacities Increased exposure – increasing frequencies of climate-related hazards – anthropogenic impact (deforestation & urbanisation) In 2000, 1 in 30 people worldwide were affected by natural hazards
1950
Increasing Vulnerability: Megacity growth
2010
Global Geohazards in 2010 Fatalities Flood 67%
Economic loss
Quake & volcano 4% Windstorm 15%
Quake & volcano 1% Flood 53%
Other 14%
Other 14%
Total: 9,270 deaths
Total: US$ 31 billion
Windstorm 32%
Insured loss Windstorm 75%
Other 4% Flood 21%
Total: US$ 8.3 billion
Geohazards 1975-2001 Number of Natural Disasters by region
Number of fatalities by region
Global Geohazards trends •
Since ‘50s numbers of major natural disasters have increased fourfold
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Resulting economic losses have risen by factor of 14
•
Due to increasing insurance density in vulnerable areas, insured losses up 28 times
Is it becoming more dangerous? •
Rapidly growing populations (megacites) in hazard prone areas – coastal areas ! both tropical cyclones & earthquakes – Asia!
• • • • •
Poor planning and construction in high risk regions Poor enforcement of building codes Inadequate public awareness and education Limited financial and technical resources Environmental degradation & climate change
•
During ‘70s and ‘80s ! 820 million people affected
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Population in 2020 ! ~8 billion
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20% of the world’s population currently live in MEGACITIES (populations in excess of 8 million)