“Historical Impact Craters: DID A BOLIDE IMPACT CAUSE CATASTROPHIC TSUNAMIS IN AUSTRALIA AND NEW ZEALAND?”
Originally presented 17 Apr 2004
Introductory Presentation by Dr. Michael J. Passow
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Earth Science Content
DID A BOLIDE IMPACT CAUSE CATASTROPHIC TSUNAMIS IN AUSTRALIA AND NEW ZEALAND?
Dallas Abbott and her colleagues have been exploring evidence that some historical tsunami events in the South Pacific resulted from bolide (asteroid or meteorite) impacts, rather than earthquakes as previously postulated. In her presentation, she will share some of her recent research in Australia and New Zealand to test her theories. She and her co-authors made a presentation at the Geological Society of America Annual Meeting in November 2003, based on this Abstract:
ABBOTT, Dallas H., MATZEN, Andrew, and PEKAR, Stephen F.
Lamont-Doherty Earth Observatory, Route 9W, Palisades, NY 10964,
dallas@ldeo.columbia.edu and BRYANT, Edward A., Faculty of Science, University of Wollongong, Wollongong, Australia, 2522
Goff attributes coastal abandonment in New Zealand at 1500 A.D. [1] to an earthquake-induced tsunami event. However, the largest
historical earthquakes produced maximum tsunami runups of 40 to 60 meters. On Stewart Island, New Zealand, beach sand is present ~220 meters above sea level at Hellfire Hut and ~150 meters above sea level at Mason Bay. In eastern Australia, there are mega sunami deposits with maximum run-ups of over 130 meters and a C-14 age of ~1500 A.D[2]. Megatsunami deposits occur on the eastern side of Lord Howe Island in the middle of the Tasman Sea, implying a source crater for the tsunami further east. We named this source crater Mahuika for the Maori god of fire. Mahuika crater is 20±2 km wide and >153 meters deep. It is on the New Zealand continental shelf at 48.3 S, 166.4E. Several pieces of evidence point to Mahuika as the source crater for the 1500 A.D. event. The first is that the crater lies on a great circle path from Australia oriented at about a 45-degree angle to the general trend of the eastern Australia coast. Mega tsunami deposits near Wollongong and at Jervis Bay, Australia suggest a tsunami wave oriented at this angle to the coast. The second is the sub bottom depth of the impact deposits. We have found impact ejecta in all of the dredges near the crater. Because marine sediments are deposited at a rate of about 1 cm per thousand years, this is expected if the impact deposit is only 500 years old. We are seeking C-14 dates to confirm this. The third is the distribution of tektites, which are found on the opposite side of the crater from the direction of impactor arrival[3]. Although we found impact ejecta in many samples, only some samples contained tektites. All
tektite-bearing samples are located SE of the crater, in the opposite direction from SE Australia, where the impact fireball was seen by
the aborigines[2].
References: [1] Goff, J.R. and B.G. McFadgen, Seismic driving of nationwide changes in geomorphology and prehistoric settlement-a 15th Century New Zealand example. Quaternary Science Reviews, 2002. 21: p. 2229-2236. [2] Bryant, E., Tsunami: The Underrated Hazard. 2001, Cambridge, UK: Cambridge University Press. 320. [3] McCall, G.J.H., Tektites in the Geological Record. 2001, London: Geological Society of London. 256.
Technology Tips for the Classroom
by Dr. Cristiana Assumpção
For information on educational technologies and ideas on how to use the Earth2Class materials in your classrooom, see the tutorials in the MENTORING section of our website http://www.earth2class.org/mentoring/technology.htm
Resources
SELECTED WEB SITES ABOUT IMPACT CRATERS
Terrestrial Impact Craters site—Calvin J. Hamilton
http://www.solarviews.com/eng/tercrate.htm
Educator’s Guide to Impact Craters
http://www.solarviews.com/eng/edu/craters.htm
Asteroid and Comet Impact Hazards
http://impact.arc.nasa.gov/index.html
Lunar and Planetary Laboratory, University of Arizona
http://www.lpl.arizona.edu/SIC/impact_cratering/intro/
Terrestrial Impact Craters, 2nd ed. by Christian Koeberl and Virgil L. Sharpton
http://www.lpi.usra.edu/publications/slidesets/craters/
Hawai’i Space Grant College Teacher Page
http://www.spacegrant.hawaii.edu/class_acts/CratersTe.html
http://www.spacegrant.hawaii.edu/class_acts/CrateringDoc.html
Impact Cratering on a Rainy Day
http://www.teacherlink.usu.edu/tlnasa/units/PlanetaryGeology/9.pdf
Explore Craters
http://www.kidscosmos.org/kid-stuff/craters.html
“Crater Crazy” by Andrea Gianopoulos
http://www.astronomy.com/content/static/parentsteachers/activities/cratercrazy.asp
SELECTED WEB SITES ABOUT TSUNAMIS
University of Washington “Tsunami!” http://www.geophys.washington.edu/tsunami/intro.html
USGS Coastal & Marine Geology Program
http://walrus.wr.usgs.gov/tsunami/
FEMA Hazards—Tsunamis
http://www.fema.gov/hazards/tsunamis/
SELECTED WEB SITES ABOUT NEW ZEALAND AND PACIFIC TSUNAMIS
DID A BOLIDE IMPACT CAUSE CATASTROPHIC TSUNAMIS IN AUSTRALIA AND NEW ZEALAND?
ABBOTT, Dallas H.1, MATZEN, Andrew1, BRYANT, Edward A.2, and PEKAR, Stephen F.1
(1) Lamont-Doherty Earth Observatory, PO Box 1000, Palisades, NY 10964-8000, dallas@ldeo.columbia.edu, (2) Faculty of Science, Univ of Wollongong, Wollongong, 2522, Australia
http://gsa.confex.com/gsa/2003AM/finalprogram/abstract_65239.htm
New Zealand Hazard Watch
http://www.gns.cri.nz/hazardwatch/latest/index.html
Tsunami Sites in New Zealand
http://www.usc.edu/dept/tsunamis/newzealand/
Pacific Tsunami Warning Center
http://www.prh.noaa.gov/ptwc/abouttsunamis.htm