DETERMINING THE LOCATION OF THE NORTHRIDGE BLIND FAULT
By Arwen
3
Vidal ,
Lucy
1
Calvillo ,
Werner
1
Horn ,
Carol
1
Shubin ,
Gerry
2
Simila
1Department
of Mathematics, California State University Northridge
2Department of Geology, California State University Northridge
3Department of Geological Sciences, University of Colorado Boulder
Results:
Abstract:
The Northridge earthquake occurred on
January 17, 1994 with a magnitude of 6.7. There
were aftershocks that followed with a magnitude
ranging from 4.0 to 5.2. This earthquake was
caused by a blind thrust fault, since the fault did
not rupture the surface.
The purpose of this project is to determine the
location of blind fault that caused the 1994
Northridge earthquake. In order to determine its
location, two linear elastic system solvers are
used; these solvers are MATLAB PDE Toolbox
and DISLOC. Results from the solvers are
compared with the real Global Positioning
Satellite (GPS) readings and differences between
the solutions are discussed.
Conclusions:
MATLAB Graph
Future Work:
In order to improve the results and reduce error a
better algorithm needs to be designed.In
addition,we would like to consider non-homogenous
models, such models would better approximate the
true variation in the upper crustal level.
Acknowledgements:
This work was supported by
NASA MURED PAIR Program
Grant Number: NASA-NCC5-489
DISLOC Graph
Introduction:
Vert. Displacm ent vs. position
M atlab Approx.
450
45
400
35
350
30
300
given
uz(44)
20
uz(45) Disloc
displacement
40
25
displacment
MATLAB PDE Toolbox computes solutions to an
elastic system with Dirichlet boundary conditions
on the sides and bottom and with Neumann
boundary conditions on the surface of a
rectangular domain. Jet Propulsion Laboratory
(JPL) DISLOC software computes a solution for
an elastic half- space model with Neumann
boundary conditions. In each case, a crack, or
internal boundary condition was inserted in the
domain. The depth and length of the crack were
given, while the angle of inclination and the slip
(or deformation) on the crack were varied.
The two programs were compared with the GPS
readings. The results from DISLOC give a better
approximation to the GPS readings with less error.
GPS Data
given
250
phi =40,s lip=1.25m
phi=40, s lip = 1
200
phi=42, s lip = 1
uz(46)
15
150
10
100
5
50
0
-30
-20
-10
0
-5
position
10
20
30
0
-20
-15
-10
-5
0
position
5
10
15
20