16
BAMOS
Jun 2018
Lifesavers attempt to resuscitate several
of the swimmers carried out to sea. Five
people drowned in the incident and 180
were rescued.
Image: Sydney Mail, 9 February 1938
the adjacent Tasman Sea. This has not been established and is
more in the realm of conjecture. possible but a lack of more detailed meteorological information
leads to uncertainty here.
6. A meteotsunami Option a is considered the most likely because of the history
of the impact of the low pressure cell the day before—as
discussed in Section 4—and the appearance of the waves in the
photograph referred to above.
A more recent suggestion to explain the Bondi big waves
concerns the possibility of a “meteotsunami”—a tsunami-like
wave-train of meteorological, rather than seismological origins.
A meteotsunami is generated by rapid changes in atmospheric
pressure that act as drivers for water displacement. When these
changes reach a certain frequency a resonance effect can be
achieved that considerably amplifies local waves, producing
tsunami-like effects.
It is considered that this is a possibility for the February 1938
event, chiefly from the eyewitness descriptions and the
photograph of the waves themselves. However no definite
conclusion can be reached because of the lack of detailed data
on the day.
The swell wave hypothesis would therefore appear to be the
most likely explanation, with further evidence required to
support the theories of a local tsunami, or a meteotsunami
event.
References
The Sun, Monday, February 7, 1938, p 1, https://trove.nla.
gov.au/newspaper/article/231117390?searchTerm=bondi%20
%2B%20rescue%20%2B1938&searchLimits=.
1
2
The Central Coast Advocate, 28th February 2018, p 6.
There are four possible explanations of the Bondi waves of 6th
February 1938 The Daily Telegraph, 6th February 2015, https://www.
dailytelegraph.com.au/news/black-sunday-1938-hundreds-
washed-out-to-sea-on-bondi-beach-as-freak-waves-kill-five-
injure-dozens/news-story/2f584af7365abc298d039d42e5f2d
df1.
a. Meteorological—large swell waves emanating from the
low pressure cell off the NSW south coast Wikipedia, List of Earthquakes 1938, https://en.wikipedia.org/
wiki/List_of_earthquakes_in_1938.
b. Meteorological—a meteotsunami where localised
tsunami-like waves were generated by rapid changes in
atmospheric pressure 5
3
7. General summary
c.
Seismological—a tsunami train was produced by a distant
earthquake
d. Seismological—a tsunami train was produced by an
undersea slump in the Tasman Sea
Option c is probably the least likely because of the factors
discussed in Section 5 above. However, because of the Terrigal
event discussed in Section 3, there is the chance that a local
undersea slump occurred in the area, meaning Option d has
some credibility. Option b—that of a meteotsunami—is also
4
Geoscience Australia, Echoes of Ancient Tsunamis, http://www.
ga.gov.au/ausgeonews/ausgeonews200609/echoes.jsp.