GEOL 15 Lecture 29 2013/12/02
• Hazard Update:
• Seattle Football Fans
• Sumatra Earthquakes
• Lecture 29 Review
• Flood!
• Final Exam Material Preview
• New Material
• Tsunami
• Volcanoes
• Floods
• Mid Term I
• Mid Term II
http://www.science.earthjay.com/?p=778
https://www.facebook.com/lori.dengler/posts/10200904338882916?comment_id=
56815465&ref=notif&notif_t=like
https://www.facebook.com/photo.php?fbid=482235371475&set=a.74925066475.78273.6276351475&comments
http://www.livescience.com/41654-seahawks-fans-trigger-earthquake.html
Seismogram showing the frequency (hz) vs. the time in seconds, which is plotted
along the horizontal axis. The Seahawks came to the line on the play that resulted in
Marshawn Lynch's touchdown run at somewhere between 98 and 100 seconds on
the graphic.
From: John Vidale, director of the PNSN
http://seattletimes.com/html/seahawksblog/2013897125_seismictimelineofmarshawnlynchstouchdownrun.html
101 - 103: Ball hiked.
105 - 107: Marshawn Lynch
hits the hole.
107 - 109: Lynch breaks
through the line.
110 - 112: Lynch breaks
another tackle.
112 - 114: Lynch shoves
Saints cornerback Tracy
Porter, knocking him 5 yards
downfield.
117 - 119: Lynch crosses the
goal line, corresponding to
the biggest burst of energy.
159 - 161: Extra-point is
kicked by Olindo Mare.
179 - 181 Possibly the replay
was shown in the stadium.
168 - 170: Replay possibly
shown in slow motion.
213 - 215: Seattle kicks off to
the Saints, play resumes.
FLOOD!
What is a flood?
A flood is an event where water inundates
land that is normally dry. Floods are a
natural process that can be caused by a
number of factors and affected by human
activities. Floods occur at irregular
intervals and no two floods are the same.
Floods can occur suddenly Sudden, heavy and
intense rainfall can cause floods to quickly rise in
the minutes or hours that follow. These are known
as flash floods and are typically associated with
relatively small catchment areas.
Floods can occur slowly In large catchment areas,
rainfall can build up over hours, days or weeks. The
runoff from this rainfall may create significant
floods that inundate large areas of land for days,
weeks or months.
Most of the largest known floods of the Quaternary Period resulted
from breaching of dams formed by glaciers or landslides.
• Types:
• Ice-Dam or Landslide-Dam Failure
• Lake Overflow (many kinds)
• Volcanic Eruption
• Ice Jam or Snowmelt
• Meteorological/Rainfall (most common)
The late-Pleistocene Missoula floods in the Pacific Northwestern United States were
some of the largest ever to have occurred on Earth. The floods resulted from the
repeated breaching of an ice dam formed from a lobe of the Cordilleran Ice Sheet
that blocked the present-day Clark Fork River and created an immense lake known as
glacial Lake Missoula.
http://hugefloods.com/LakeMissoula.html
An illustration of factors that contribute to floods.
http://www.chiefscientist.qld.gov.au/publications/understanding-floods.aspx
Basin/Catchment - The
surface area of land that
collects and drains water
into a river or other
waterway.
http://ut.water.usgs.gov/publications/fs245-96/
A manual stream gauging
station on the Fitzroy River,
Rockhampton, January 2011.
Note the historical reference
to heights of previous floods:
1918, 1954, and 1991.
http://waterwatch.usgs.gov/?m=mkrc&sno=11475000
“flashy”
Luckiamute River, Jan. 19, 2012
TSUNAMI!
Atwater et al., 2005
Atwater et al., 2005
Patton, 2013
CGS, 2009
Geology 15 Activity 10 B
Tsunami and Tide Gage Records
2001 Peru
Tavera et al., 2006
Tavera et al., 2006
Tsunami deposit at La Quinta overlying agricultural soil. A thin
layer of mud divides the deposit into two distinct layers.
Jaffe et al., 2003
VOLCANO!
Lava mapped in 17th and 18th centuries
http://www.old-map-blog.com/wp-content/uploads/2010/01/Vesuv_Mount_Vesuvius.jpg
Excavated in 20th century
Herculaneum AD
79. A large number
of people were
sheltering in this
seaside boathouse.
The ancient Roman
town was destroyed
by the same Mt.
Vesuvius eruption
that took out
Pompeii.
https://www.pinterest.com/pin/470978073501952619/
• Hot Spots
• Rifts
• Subduction Zones
CASCADES VOLCANO!
http://volcanoes.usgs.gov/images/pglossary/VolRocks.php
http://volcanoes.usgs.gov/images/pglossary/basalt.php
Basalt is a hard, black volcanic rock with less than about 52 weight
percent silica (SiO2). Because of basalt's low silica content, it has a low
viscosity (resistance to flow). Therefore, basaltic lava can flow quickly
and easily move >20 km from a vent. The low viscosity typically allows
volcanic gases to escape without generating enormous eruption
columns. Basaltic lava fountains and fissure eruptions, however, still
form explosive fountains hundreds of meters tall.
http://volcanoes.usgs.gov/images/pglossary/andesite.php
Andesite is a gray to black volcanic rock with between about 52 and 63
weight percent silica (SiO2). Andesite magma commonly erupts from
stratovolcanoes as thick lava flows, some reaching several km in length.
Andesite magma can also generate strong explosive eruptions to form
pyroclastic flows and surges and enormous eruption columns. Andesites
erupt at temperatures between 900 and 1100° C.
http://volcanoes.usgs.gov/images/pglossary/dacite.php
Dacite lava is most often light gray, but can be dark gray to black. Dacite
lava consists of about 63 to 68 percent silica (SiO2). It is one of the most
common rock types associated with enormous Plinian-style eruptions.
When relatively gas-poor dacite erupts onto a volcano's surface, it
typically forms thick rounded lava flow in the shape of a dome.
http://volcanoes.usgs.gov/images/pglossary/rhyolite.php
Rhyolite is a light-colored rock with silica (SiO2) content greater than
about 68 weight percent. Sodium and potassium oxides both can reach
about 5 weight percent. Common mineral types include quartz, feldspar
and biotite and are often found in a glassy matrix. Rhyolite is erupted at
temperatures of 700 to 850° C.
Volcanic Hazard Mt. Lassen
• Mid Term I
• Scientific Method
• Energy
• Earthquakes
• Stress and Strain
• Elastic Rebound Theory
• Earth’s Structure
• Plate Tectonics
• Plate Boundaries
• Plate Movement
• Faults
• Intensity/Magnitude
• Seismology
• Mid Term II
• Earthquake Magnitude
• Earthquake Cycles
• Focal Mechanisms
• Paleoseismology
• Geodesy
• Final
• TSUNAMI!
• VOLCANO!
• FLOOD!