Open AccessFrequency–magnitude statistics and spatial correlation dimensions of earthquakes at Long Valley caldera, California
Author(s) -
Barton D. J.,
Foulger G. R.,
Henderson J. R.,
Julian B. R.
Publication year - 1999
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.1999.00898.x
Subject(s) - geology , seismology , magnitude (astronomy) , caldera , fault (geology) , induced seismicity , fault plane , earthquake swarm , earthquake magnitude , fractal dimension , seismic zone , fractal , volcano , geometry , scaling , mathematical analysis , astronomy , physics , mathematics
Intense earthquake swarms at Long Valley caldera in late 1997 and early 1998 occurred on two contrasting structures. The first is defined by the intersection of a north‐northwesterly array of faults with the southern margin of the resurgent dome, and is a zone of hydrothermal upwelling. Seismic activity there was characterized by high b ‐values and relatively low values of D , the spatial fractal dimension of hypocentres. The second structure is the pre‐existing South Moat fault, which has generated large‐magnitude seismic activity in the past. Seismicity on this structure was characterized by low b ‐values and relatively high D . These observations are consistent with low‐magnitude, clustered earthquakes on the first structure, and higher‐magnitude, diffuse earthquakes on the second structure. The first structure is probably an immature fault zone, fractured on a small scale and lacking a well‐developed fault plane. The second zone represents a mature fault with an extensive, coherent fault plane.