A
◆
▼
45˚
▼
▼
▼
▼
▼ ▼
▼
▼ ▼
▼
▼
▼
▼
◆
◆
◆
continental lithosphere
A
◆
craton
Appalachians
Grenville
AM
oceanic
lithosphere
fossil
anisotropy
◆
A’
H?
c?
tion fabri
delamina
▼
NEA
?
L?
flow
in
asthenosphere
40˚
A’
-80˚
-75˚
-70˚
-65˚
Teleseismic and regional seismisity in 1997-98
30˚N
cross - Mb>4 "local"
diamond - 6>Mb>5 "regional"
Mb>6.0
90˚W
60˚W
30˚W
Figure 2. TopRight: Seismic observatories in the region: permanent stations (open triangles),
portable stations with over 1 year of data (dots), POLARIS array (solid triangles). Proposed
portable deployment is shown with diamonds. Sites are tentative. TopLeft: Schematic cartoon of
subsurface features we seek to identify and explore, drawn (not to scale) along the line A-A’.
AM - Adirondack Mountains; NEA - New England Anomaly (low seismic velocities); H, L - Hales
and Lehman discontinuities.
Bottom panels illustrate distribution of seismic sources in a 2-year period that will form the dataset
for tomographic imaging of the region, and for waveform analysis at portable netwrok sites.