Certain places in the world like those near plate boundaries are prone to earthquakes, volcanic eruptions and tsunamis. Such natural hazards pose dangers to people who live there and have significant impact on their quality of life. In examining the spatial patterns of these natural hazards and why such patterns exist, students have to explore the concept of plate tectonics and understand how plate movements resulting from internal earth processes create mountain systems, some large-scale landform features and tectonic hazards around the world. They will examine how and why the impact of these tectonic hazards vary greatly from place to place and consider the decision-making process that leads people to adopt certain responses when deciding to live in hazard-prone areas. Although Singapore is not at the plate boundaries, we do experience tremors and effects associated with earthquakes and volcanic eruptions occurring in neighbouring countries. Through studying this topic, students will gain an appreciation of the constraints people face and the reasons behind the different choices people make in similar situations.
Plate tectonics is the theory that explains how plates move. Earth’s outer shell is divided into several plates that float over the mantle, the molten layer above the core. The plates act like a hard and rigid shell compared to Earth’s mantle. Imagine an egg. The egg shell is like the outermost crust.
Points of difficulty
- Defining plate tectonics. Is it a force, scientific theory, mountain-building, structural feature of the Earth, concept, or other process as often implied?
- Constructing a permanent concept of plate tectonics that differs from continental drift. It is easier to envision continental drift where blocks of solid continental crust plow through solid oceanic crust.
- Envisioning three-dimensional processes.
- Understanding the difference between a map view and a cross-sectional view.
- Several mountain ranges are difficult to place in a simple view of tectonics because they are not well understood (Sierra Nevada and Rockies) or they exist as relic of past. There is an absence of the tectonic activities that produced them (Appalachians) in present day context.