17 April 2016: Ecuador earthquake of 7.8 magnitude kills dozens

Ecuador is well used to earthquakes. There have been seven 7.0 magnitude or greater events within 250km of this latest tremor since 1900. And some of these have resulted in very considerable loss of life, not just from the shaking but also from tsunami waves. The country sits on the so-called "Ring of Fire" - the arc of high seismic activity that extends right around the Pacific basin. At its location, Ecuador fronts the boundary between the Nazca and South American tectonic plates. These are vast slabs of the Earth's surface that grind past each other at a rate of about 65mm per year. The Nazca plate, which makes up the Pacific Ocean floor in this region, is being pulled down (subducted) and under the South American coast. It is a process that has helped build the Andes and Ecuador's many volcanoes, including the mighty Chimborazo. Models that try to forecast the likely casualty numbers from the nature of the quake and local building construction methods indicate this event could be very serious, with the number of deaths running into the hundreds. Analysis: Jonathan Amos, BBC science correspondent. From: http://www.bbc.com/news/world-latin-america-36065551

Word box Tectonic plates

Tremor = small earthquake

To grind = to rub together harshly

Continental drift

To collide = to bump into each other

Boundary

Forecast

To shift apart

Convection currents

Cold descending slab

Subduction = when plates ride under each other

mountain ranges

When a rock is deforming in a brittle fashion

deformation of the sea floor

Tsunami

Strain

To bend

Foreshocks = Preliminary earthquakes

Aftershocks

Richter magnitude scale = logarithm of the ratio of the amplitude of the seismic waves to an arbitrary minor amplitude

To slide past each other

The edges of the plate

Stored up energy is released

The energy radiates outward from the fault in all directions

Seismic waves

To predict = to forecast

Reverse fault = thrust

Normal fault

Strike-slip fault

To trigger

Instruction: imagine you're a science correspondent for a newspaper and you have to prepare an interview to explain why earthquakes often hit contries along the peri-Pacific belt. To fully succeed in this exercise, you must use at least 10 words featuring in the word box. (one of you will count while others will ask questions about geology mechanisms responsible for earthquakes)