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October 16, 2006

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ASK THE EXPERTS : GEOLOGY


	Browse Subjects:

What is quicksand?

What is a geyser?

Why is oil usually found in deserts and arctic areas?

How do volcanoes affect world climate?

How do scientists determine the composition of the interior of Earth and other planets?

How was the Richter scale for measuring earthquakes developed?

What conditions are necessary for an underwater earthquake or volcanic eruption to cause a tsunami?

Did the earthquake that spawned the recent Indian Ocean tsunami affect the earth's rotation?

How can the weight of Earth be determined?

What causes a volcano to erupt and how do scientists predict eruptions?

What causes the periodic reversals of the earth's magnetic field? Have there been any successful attempts to model the phenomenon?

Why are impact craters always round? Most incoming objects must strike at some angle from vertical, so why don't the majority of impact sites have elongated, teardrop shapes?

Why do regular, wavelike shapes form when the wind blows over the sand on the beach for a long time? And what determines the spacing (frequency) of these waves?

What ever happened to the theory of periodic mass extinctions, which stated that major extinctions occur every 26 million years? Is it widely accepted? And when was the last such extinction--have there really been two of them since the dinosaurs died off 65 million years ago?

I am wondering about the significance of the recent report that the earth's solid core rotates slightly faster than the earth's surface. Is this a cause or an effect of the earth's magnetic field? Does the slowing of the earth because of the moon's gravity also contribute to the phenomenon?

What do we know about the origin of the earth's oceans? Is it more likely that they derive from icy comets that struck the young earth or from material released from the earth's interior during volcanic activity?

Is it true that the strength of the Earth's magnetic field is decreasing? What's the effect?

Why does the Earth's magnetic field flip over the course of history? What attempts have been made to model this phenomenon mathematically?

Are the Earth's magnetic poles moving? How do navigators adjust to this change?

Why is the earth's core so hot? And how do scientists measure its temperature?

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