But the size of this one, 7.7 on the magnitude scale.

Makes it one of the largest in living memory for the millions of people impacted by its shock waves.

And that's what you can see here, a shake map showing the intensity of ground movement estimated by the US Geological Survey, this dark orange is violent shaking, likely resulting in high casualties and extensive building damage.

It's a populated area too, the city of Mandalay has 1.2 million inhabitants, the capital Yangon, millions more.

But images of extensive damage are coming in from across Myanmar and beyond, suggesting the force and destruction of this quake was widespread.

All made worse of course by aftershocks, the worst a magnitude 6.4 shock happening close by just minutes after the main quake.

Myanmar straddles the boundary between the vast Eurasian tectonic plate and the Indian plate that's moving slowly north, piling up stress on the rocks beneath.

Specifically along the 1,200 km long Sagaing fault line running right next to Mandalay and many other populous cities.

The quake happened when the strain on that fault was suddenly released and in geological terms at least at a shallow depth, just 10 kilometers or six miles down.

And the closer the surface, the greater the damage, locally that's in the form of intense shaking due to high frequency vibrations, but lower frequency shock waves travel further.

And tall buildings are most vulnerable to the slower movement they cause, perhaps explaining the collapse of tower blocks as far away as the one under construction in Bangkok.

Previous earthquakes in Myanmar have caused damage like this to some of its oldest buildings, but this is the most powerful quake in this region since the 1940s, predating modern earthquake building codes.

The fear is some older structures that survived previous quakes won't have endured this one, and of course it's the buildings in which people live that are the greatest risk factor when it comes to earthquake casualties.