Tectonics Flashcards
What volcanoes occur at a divergent boundary
Low viscosity
What earthquakes occur at a divergent boundary
Low magnitude
What volcanoes occur at a convergent boundary
high viscosity and high silicia content as large amount of gas released - Philiphenes
What earthquakes occur at a convergent boundary
High magnitude
what earthquakes occur at a collsion boundary
high magnitude
what earthquakes occur at a conservative boundary
high magnitude
4 theories of plate tectonics
Wegners continental drift, sea floor spreading , holmes heat hypothesis,paleo magnitism
4 primary hazards of volcano
ash fall, volcanic gas, pyroclastic flow, lava flow
secondary hazards of volcanos
jokulap , lahars
cause of intra plate volcano
hot spot- rising magma under weakness often cause less viscos eruptions
causes of intraplate earthquakes
ancient faults
4 parts of earth
core, athenosphere , lithosphere , crust
focus
where pressure is released underground
epicentre
point on surface directly above focus
what is a shallow focus
0-70km
what is a deep focus
70-700km
P waves
Fastest wave, least damage
L waves
most damage
S waves
make ground shake
wavelength of tsunami
long at sea, decreases as reaches land
amplitude of tsunami
short at sea, increases as reach land
velocity of tsuanmi
slows as reaches shallow water
Sign a tsuanmi is going to occur
Water is drawn back
Trends of tectonic disasters
remained the same - more people affected
more are being recorded s can look like they are more frequent
trends of hydro meterological disasters
more common - global warming has meant that more of the ocean is above 26.5 degrees
multiple hazard zones are
tectonically active, geologically young
hawaii
Forecasts
percentage chance
Seisometer
records minor earthquakes
tiltmeters
record volcanoes bulging
gas spectrometres
analyse gas emissions