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used these reports to prepare a map on which each observation was marked
by a red circle, with an arrow indicating the direction of motion, a system
he compared to that of weather maps.
14
As Martin revealed to the Princeton
geologist Charles rockwood, “the labor involved in these preparations was,
as may readily be seen, very great; and it was quite out of proportion to
the results. No seismic center or central line could be detected.” A majority
reported that the shock traveled from southwest to northeast, and Martin
decided “on other grounds that such was the true course,—upward along
the line of strike of all the rocks of this region. the cracks produced in the
ground at Closter, New Jersey had a course transverse to this, and confirmed
my impression.” Martin shared these conclusions with “a very intelligent
and somewhat scientific reporter” at the
New York
Tribune,
but the paper
“mixed up my remarks as to the crystalline rocks greatly.”
15
No wonder Mar-
tin's efforts proved frustrating: scientists have since found that earthquakes
in the northeastern United States do not tend to occur along known faults.
the geologic structure responsible for earthquakes in this region remains
an “enigma.”
16
While Martin worked up these results, information reached him from
farther afield. he received “two remarkable letters . . . detailing a marked
disturbance of very similar character in eastern Massachusetts, on the same
afternoon between 5:30 and 6.” he also read a report in
Nature
of an earth-
quake atop the Pic du Midi in the Pyrenees at 4:45 a.m. on 11 Decem-
ber—nearly coinciding with the temblor in New York. According to
Nature,
the original source of that information was apparently a small-town French
weekly with the romantic title
L'Echo des Vallées.
then Martin read of vol-
canic eruptions in Iceland, beginning in December and continuing through
January. the famed British explorer richard Burton drew his account of the
eruptions primarily from critical readings of Icelandic newspapers: “the lo-
cal papers . . . give ample accounts of the late movements. . . . Much of the
matter has been translated and published by our home press, but there are
interesting details which have not been noticed. Generally—allow me to
remark—the accounts, though utterly unscientific, bear an aspect of sobriety
and truthfulness wholly wanting in the older Icelandic descriptions . . . , and
they show that the spirit of enterprise has not wholly died out in Iceland.”
17
Faced with these new clues, Martin wrote to rockwood in mid-June that he
would have to postpone further publication: “But now, we have these re-
markable accounts of outbreaks, and disturbances in Iceland during the past
winter; and the question at once occurs to me, when did these begin? . . .
My impression from all our accounts, is very strong, that the shock in our
region was
deep
and wide-spread. the two (distinct) afternoon shakings,
