Garrett Apuzen-Ito Professor of Geophysics

Department of Geology & Geophysics SOEST, University of Hawaii-Manoa

I. Our Dynamic Earth Expressed through the Creation of the Philippine Archipelago

Objectives:1) Overview plate tectonics & Earth’s major forms of volcanism2) Summarize origin & evolution of the Philippine Archipelago

Plate Tectonics

The rigid outer shell of the Earth, called the lithosphere, is broken up into many rigid segments of different sizes and shapes.

Pangaea (240 Myr ago)

First evident in the continent jigsaw puzzlePresent Day

Plate Tectonics

Types of Plate Boundaries

ConvergentDivergent

Transform

Plate Tectonics is the Surface Expression of Mantle Convection

Hot (~3000 oF), Ductile but (mostly) solid

Upper mantle

seafloorspreading

subductionsubduction

How Fast Do the Plates Move?

seafloorspreading

subductionsubduction

Sloooowly: 1-10 cm/yr

That’s about 100 Million yrs!

How Long Did it Take to Create the Pacific Basin?

seafloorspreading

subductionsubduction

1-10 cm/yrAt 10 cm/yr & life time of 100 yrs how much finger nail is grown?10 m

A 1000 human life times gives 10km

A 1000 x 1000 human life times gives 10,000km

Three Main Origins of Volcanism

Mid-ocean ridge volcanismcreates the seafloor.

60% of Earth’s surface!

Three Main Origins of Volcanism

Three Main Origins of Volcanism

Arc volcanism behindsubduction zones.

“Pacific Ring of Fire”

Tectonic Environment of the Philippines

How to Prepare for your Talk

1) Collect and learn your material2) Decide on your main points3)Prepare slides that start lead your forward towards your main points4) Practice (for effect, timing, performance)5) Adjust your slides appropriately6) Practice out loud to yourself