NSF Org:	EAR Division Of Earth Sciences
Recipient:	UNIVERSITY OF NEW MEXICO
Initial Amendment Date:	November 12, 2002
Latest Amendment Date:	March 14, 2005
Award Number:	0228849
Award Instrument:	Standard Grant
Program Manager:	Robin Reichlin EAR  Division Of Earth Sciences GEO  Directorate for Geosciences
Start Date:	January 1, 2003
End Date:	September 30, 2005 (Estimated)
Total Intended Award Amount:	$38,588.00
Total Awarded Amount to Date:	$38,588.00
Funds Obligated to Date:	FY 2003 = $38,588.00
History of Investigator:	John Geissman (Principal Investigator) geissman@utdallas.edu
Recipient Sponsored Research Office:	University of New Mexico 1 UNIVERSITY OF NEW MEXICO ALBUQUERQUE NM  US  87131-0001 (505)277-4186
Sponsor Congressional District:	01
Primary Place of Performance:	University of New Mexico 1 UNIVERSITY OF NEW MEXICO ALBUQUERQUE NM  US  87131-0001
Primary Place of Performance Congressional District:	01
Unique Entity Identifier (UEI):	F6XLTRUQJEN4
Parent UEI:
NSF Program(s):	Geophysics
Primary Program Source:	app-0103
Program Reference Code(s):	OTHR, 0000, 9150
Program Element Code(s):	157400
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

Geissman
EAR-0228849

Frictional heating during coseismic deformation can lead to the
melting of the fault rocks and formation of pseudotachylite if slip
is important. The increasingly reported existence of earthquake
lightning shows that transient coseismic electric currents of large
intensity are associated with large magnitude earthquakes (M > 6.0).
Such currents are likely to follow pseudotachylite veins because
their electric conductivity, being melts, is considerably larger than
that of the unmolten rocks. All previous and preliminary results on
fault-related pseudotachylites show that they have an anomalously
high remanent magnetization. Their remanent magnetic properties are
similar to those of lightning struck rocks, which suggests that large
electric pulses were involved in the magnetization. This project
aims at demonstrating that remanence anomalies in pseudotachylites
are generally observed and that coseismic electric currents are
responsible for it. The investigators propose to test the hypothesis
on three young pseudotachylites from seismically active fault zones
(California, Japan and Western Alps) by collecting oriented samples
for paleomagnetic studies. Samples collected at various points with
respect to the main fault plane will enable us to test the coseismic
current hypothesis. The geometry and the characteristics of the
magnetizing field will be compared with the Earth's magnetic field at
the time of pseudotachylite formation. This will provide an
independent second test for the coseismic current hypothesis. A
series of experiments will generate artificial pseudotachylites using
the friction welding method. The artificial and natural
pseudotachylites will be compared to assess the possible causes of
anomalous magnetization in natural specimens. The direct study of
coseismic currents is made difficult by their transient nature. This
problem can be circumvented by using the remanent magnetic record of
rocks affected by the electrical phenomenon. This research will
open new directions of investigation on coseismic electric currents
in fault rocks and should contribute to a better understanding of
coseismic electric phenomena
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