Lecture 13 Flashcards
Sumatra
Dec 26, 2004 8am 30 km deep Megathrust EQ, 9.1 Caused dipole acis of geomagnetic field to shift 2.5 cm, make Earth less oblate (1/billion) and increased rotation rate Tsunami, >230,000 people killed
Japan Tsunami
March 11, 2011 24 km deep (length: 390 km, width: 240km) Megathrust EQ, 8.9 Epicenter offshore from Tohoku, Japan Tsunami <22, 000 people died
Faults in Sumatra EQ
2
Thrust fault at subduction zone
Right lateral strike slip fault on land
Japan tsunami countermeasures
Offshore and onshore tsunami barriers
Natural planted tree barriers
Vertical evacuation building
Periodic evacuation training
DART
Seafloor bottom pressure recording system
Detects tsunamis as small as 1 cm
Moored surface buoy from real-time communications
Two way communication from seafloor system and Tsunami warning center
Allows set stations to anticipate tsunamis and retrieve high resolution data
Standard mode data, 24 estimated sea-lecel height observations at 15 min intervals
MOST model
Numerical model
Method-of-splitting-tsunami model
Input location and magnitude of EQ
Make ground deformation model
Estimate vertical displacement of ocean floor (set as displacement of sea surface)
Run different simulations
Adjust model as more information becomes available
Adjust tsunami source when DART data becomes available
Updata tsunami warnings
Tsunami height
The height of the wave until it reaches the shoreline
Indundation distance
Maximum water penetration in land (distance from average coastline at high tide)
Run-up height
Height above average high tide level at the point of maximum distance inland
How to measure ID and RUH
Watermarks on buildings, trees, and walls by using a laser range finders, a real‐time kinematic (RTK) GPS receiver with a cellular transmitter, and total stations.
Inundation and run-up are sensitive to:
High‐resolution bathymetric and topographic data
Wave breaking
diffraction
Infrastructure
