GSA Today
Zealandia: Earth’s Hidden Continent
Cover Image
2 GNS Science, P.O. Box 30368, Lower Hutt 5040, New Zealand
3 SGEES, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
4 Service Géologique de Nouvelle Calédonie, B.P. 465, Nouméa 98845, New Caledonia
5 School of Geosciences, University of Sydney, NSW 2006, Australia
Abstract
A 4.9 Mkm
2 region of the southwest Pacific Ocean is made up of continental crust. The region has elevated bathymetry relative to surrounding oceanic crust, diverse and silica-rich rocks, and relatively thick and low-velocity crustal structure. Its isolation from Australia and large area support its definition as a continent Zealandia. Zealandia was formerly part of Gondwana. Today it is 94% submerged, mainly as a result of widespread Late Cretaceous crustal thinning preceding supercontinent breakup and consequent isostatic balance. The identification of Zealandia as a geological continent, rather than a collectio
Introduction
The Valdivia Earthquake formed one of the most deadly earthquakes that have been ever witnessed on the planet. It is also known as the Great Chilean earthquake. It possessed a magnitude of about 9.4-9.6 according to records from studies.
Important dates of the earthquake
This earthquake disaster occurred in the year 1960 on 22
nd May. The disaster was experienced in the afternoon on that mentioned day and lasted for approximately ten minutes.
Geographical location of the earthquake
Lumaco acted as the main center of the impacts experience form the major earthquake disaster which lies just 570km south of Santiago (Lorenzo et al, 2014). The most affected city was Valdivia. The Chilean coasts were battered with localized tsunamis that resulted from the tremor. The major tsunami was witnessed across the ocean of pacific and extended towards Hilo of Hawaii. Waves which were as strong 10.7m were experienced at a distance of about 10, 000km from the epicenter, japan and
Dubbed MORVEL for mid-ocean ridge velocities, the new model is detailed in
Geophysical Journal International. The work builds on a 1990 study describing tectonic plate velocities. During the past 20 years, researchers have incorporated more and higher-quality data to improve the model s resolution and precision. This model can be used to predict the movement of one plate relative to any other plate on the Earth s surface, explains University of Wisconsin-Madison geophysicist Chuck DeMets. Plate tectonics describes almost everything about how the Earth s surface moves and deforms, but it s remarkably simple in a mathematical way.
T
his figure shows the boundaries of the tectonic plates that cover the Earth’s surface. The two-letter codes are plate name abbreviations; those in black are included in the model.