Alan Ruffman

West Coast tides during Cascadia Subduction Zone tsunamis

Low, neap tides occurred along the West Coast of the United States and Canada around 0500 UT January 27, 1700, a time for the last major Cascadia earthquake/tsunami based on teletsunami arrival times in Japan [Satake et al., 1996]. However, high-range perigean spring tides occurred only a week later, illustrating how accurately occurrence times must be known to constrain the regions background water levels during such events. The ranges of background water levels increase northward from 3 m at Monterey to 8.5 m at Queen Charlotte, as estimated from the amplitudes of perigean spring tides and subtidal winter fluctuations.

Titanic's unknown child: The critical role of the mitochondrial DNA coding region in a re-identification effort

This report describes a re-examination of the remains of a young male child recovered in the Northwest Atlantic following the loss of the Royal Mail Ship Titanic in 1912 and buried as an unknown in Halifax, Nova Scotia shortly thereafter. Following exhumation of the grave in 2001, mitochondrial DNA (mtDNA) hypervariable region 1 sequencing and odontological examination of the extremely limited skeletal remains resulted in the identification of the child as Eino Viljami Panula, a 13-month-old Finnish boy. This paper details recent and more extensive mitochondrial genome analyses that indicate the remains are instead most likely those of an English child, Sidney Leslie Goodwin. The case demonstrates the benefit of targeted mtDNA coding region typing in difficult forensic cases, and highlights the need for entire mtDNA sequence databases appropriate for forensic use.

A numerical model for the Halifax harbor tsunami due to the 1917 explosion

Abstract The explosion of the ammunition ship Mont Blanc in Halifax Harbor produced a strong tsunami locally. There was not an operational tide gauge at the time to document the changes in sea level, but there are several narrative reports of extreme high and low water. In this study we examine the tsunami by looking at integrating three different aspects. We have collected narrative reports to see what quantitative information might be obtained from them. We have estimated the height of the initial mound of water that would be produced from an explosion of 2.9 kilotons in the harbor narrows where the Mont Blanc grounded. Finally, we have formulated a numerical model to follow the progress of the wave through the harbor, into Bedford Basin and out toward the Atlantic Ocean. Various analytical, empirical, and numerical models on explosion‐generated waves provide an estimate for the tsunami amplitude as a function of the explosive charge and limited by the water depth. For the Halifax explosion, the tsunami...

Magma injection directions inferred from a fabric study of the Popes Harbour dike, eastern shore, Nova Scotia, Canada

A 15-m-wide dike at Popes Harbour on the eastern shore of Nova Scotia shows an increase in both the size (up to 1 m) and density (up to ∼50%) of predominantly pelitic xenoliths toward the dike center. These features reflect flowage differentiation processes during dike emplacement. Flow direction is indicated by sillimanite xenocrysts that represent the unassimilated products of xenolith disaggregation. The xenocrysts are highly aligned parallel to the dike margins (northwest-southeast), with a mean plunge of 20°SE, suggesting that the magma last moved, and may have been injected, in a subhorizontal, northwestward direction. The available information indicates that lateral injection of magma in mafic dikes is more common than predominantly vertical movement. This study shows that an analysis of fabrics in mafic dikes should be useful in further evaluating the role of lateral magma injection in dike formation.

Potential for large-scale submarine slope failure and tsunami generation along the U.S. mid-Atlantic coast: Comment COMMENT

[Driscoll et al. (2000)][1] cite the November 18, 1929, magnitude 7.2 earthquake and tsunami at the mouth of the Laurentian Channel south of the Burin Peninsula of Newfoundland, Canada, as one such known passive continental margin, submarine, tsunamigenic landslide. They cite “51 dead along the

Holocene rise of relative sea level at Sable Island, Nova Scotia, Canada: Correction and note

The map provided in Scott et al. (1984) showing the three 1981 boreholes on Sable Island is incorrectly drawn. The borehole locations are shown correctly on the published map relative to the various geographical features of the island, but they are shown incorrectly with respect to the geographical grid. If the geographical coordinates of the three boreholes are determined and digitized from the map provided in the paper and then plotted on the most current bathymetric map, all three boreholes plot well out in the ocean to the south of the island. Sable Island has a reputation for minor shifts in its shoreline at the spits, but it has not shifted to such a degree in the past few years as to put any of the original, onshore borehole locations into the offshore area at the present time.

Comment on “A New Analysis of the Magnitude of the February 1663 Earthquake at Charlevoix, Quebec” by John E. Ebel

Modern seismologists perhaps too easily become enamored of their modern seismographs and instrumental arrays that can do wonders for the analysis of recent events. In the instrumental era, we tend to forget that such recordings are barely 110 years old and that we are trying to understand seismic‐source zones with an activity return period in the order of 300–600 years. Documenting and understanding preinstrumental historic events is still a necessary endeavor and requires the input of our allies in the field of history. I welcomed John E. Ebel’s re‐examination of the 5 February 1663 earthquake (Ebel, 2011). As someone who has worked on the historical seismicity of parts of Atlantic Canada, I appreciate the great difficulty the author had in digging out data from the seventeenth century. Early European settlement in eastern Canada was very sparse at the time, many settlers were not literate, and even fewer could afford the cost of a pen and ink and the paper to keep a journal or diary—or the time that a journal takes away from the task of subsisting in the harsh environment of their New World. The author kindly credited me (p. 1027, col. 1) with information with respect to the 5 February 1663 event being felt and to having rattled cooking utensils and tableware in the village of St. Peters in southeastern Cape Breton Island in Acadia (now the Province of Nova Scotia). The credit for these data rightly should go to Ronnie‐Gilles LeBlanc, a historian at Parcs Canada, Centre de services de l’Atlantique in Halifax, Nova Scotia; I was only a conduit. In fact it is not quite certain where Nicolas Denys was living on 5 February 1663. M. LeBlanc’s exact words of 9 September 2009 to me on this location were, “It is not clear whether Denys was …