Toward a Earthquake Ontology

1
Toward a Earthquake Ontology

• For the purposes of seismic hazard analysis, an
  earthquake is a motion event sequence.
• fault slip ? wavefield ? ground motion ?
  seismogram

2
Motion Event Sequence

• A motion event sequence is a nesting of motion
  events
• M0 ? M1 ? M2 ? ? MN
• or
• MN( ( M2( M1( M0 ) ) ) )
• As the notation implies, motion event Mn-1 does
  not depend on Mn (an approximation).

3
Motion Events

• A motion event is a vector-valued displacement
  function of space and time
• M u(r, t) for r ? R (region of M)
• and t ? T (interval of M)

4
Types of Motion Events

• Type Motion occurs Region type
• fault slip on fault patch surface
• wavefield in earth structure volume
• ground motion at site point
• seismogram from instrument point

5
Fault Slip

• A fault is an underground surface
• A fault patch is part of a fault
• A fault slip is a motion event occurring on a
  fault patch

6
Types of Faults

• Dip-slip
• Normal
• Reverse
• Thrust (dip gt 45)
• Strike-slip
• Right-lateral
• Left-lateral
• Oblique-slip
• Dip-slip strike-slip

7
Wavefield

• A earth volume is part of the earth
• An earth structure is an earth volume that has
  anelastic parameters
• A wavefield is a motion event occurring in an
  earth structure
• A surface wave is part of a wavefield

8
Seismogram

• An instrument is at a site
• An instrument has an instrument response
• A seismogram is a motion event occurring on an
  instrument
• A surface wave train is part of a seismogram