On 4 September 2010, at 4:35am, a magnitude 7.1 earthquake, 37km away and 11km deep, smashed into Christchurch, New Zealand. Eight more large quakes over magnitude 5 hit on the same day, followed by hundreds of aftershocks. We felt lucky. The Southern Alps fault where the Australian and Pacific tectonic plates collide could have ruptured. It didn’t. No one was injured. We lost a chimney. We had a narrow escape.
On 22 February 2011, at 12:51pm a 6.3 earthquake 6km away and 6km deep hit Christchurch with a force of 2.2 G’s. One G is the force of gravity. Gravity is an accelerating force of 10 metres per second per second. The means every second you travel 10m/s (36km per hour). When this quake hit, every second, we travelled at a speed of 22 m/s (4,500kph). Sound travels at 340m/s (1,200 kph). We were hit by a force four times faster than the speed of sound.
The force was enough to open the earth’s magnetic field. Weird flickering light – all of the electromagnetic radiation that emits from the sun, but usually bounces off the earth’s magnetic field – shot through the atmosphere. A daytime aurora. Christchurch was weightless. All of the buildings within Christchurch City within an approximate 10km radius of the epicentre lifted up to 1m off the surface of the earth.
I floated up. 20cm. Or more. Just for a moment.
The magnetic field closed. The earth rippled and formed metre high waves. The height of a wave is measured from its midpoint to its crest. For every metre we were lifted up to the crest of the wave, we passed back down through its midpoint into the 1m trough of the wave. Over and over we were lifted and dropped a total of 2m as the ocean of earth tumbled moved around us and through us. Stone and bricks and glass and concrete smashed and ground and split again and again.
A shock wave that travels through earth bumps into particles that slow it down. The closer the particles are, the less the ground moves. There were lots of space between particles. People with homes close to the coast on the sand saw 1m high waves of sand travelling towards them. People with homes on the Port Hills rock heard the rock grinding. We were about half way between the Port Hills and the coast on an alluvial plain – where rivers flow. The soil under our home is fine silt and river rocks which formed about 20cm waves.
The shock wave from the ruptured fault broke the earth’s surface and punched the air. Air is less dense that rock and earth. There are a lot of spaces between particles in air, so the shock wave sped up. The earth shattered. Rocks exploded from high points on outcrops and peninsulas. Every surface beat, shuddered, jammed and kicked with the strain of it.
Imagine the sound. You can’t imagine the sound. Rocks shattering like glass. Molecules screaming apart. You can’t move, think, act.
It felled the City.
The City blew apart and buildings hit the ground with a massive thump. We were 3km from the faultline and the city centre. The sound came first, then the pressure wave struck up under our feet. Dust ballooned up in a mushroom cloud then spread outwards. Within hours we couldn’t see across the road.
The City was chaos. Screams. Shock, tears, grief, pain. Billowing clouds of dust. Sirens. Blood. Mangled limbs. In 10 seconds, 185 people died, 115 in the 1986 CTV building alone, its concrete slabs collapsed like dominoes. Survivors are injured for life. Three more large quakes hit on the same day, each one over magnitude 5, and hundreds of aftershocks.
The world looked our way. Media and emergency services arrived from everywhere. Helicopters flew overhead. The sirens went on and on.
Any quake over magnitude 5 with an epicentre within 10km of your home in any direction is a big quake. On 13 June 2011, a 6.4 and a 5.1 quake hit, 7km away and 7km deep. On 23 December 2011, a 6.0 quake hit, 9km away and 7km deep. A 5.8 quake hit on 24 December 2011. Earthquakes and aftershocks after earthquakes and aftershocks. Ten thousand earthquakes and aftershocks within one year. We were in the grip of a major quake swarm. By Valentine’s Day 2016, Christchurch had been hit by over 80 big quakes. We were punch drunk and scared.
Unless you have experienced an earthquake it is hard to understand the deep disruption fear causes to your psyche. Nothing is real. Land is water. Air is dust. You are not all right. No one around you is all right. You are on a constant adrenaline rush. You could be the woman that can move mountains, run marathons, save the world. You could be the child who just stops thinking and moving for an hour. You could be the man who runs around in circles and spout gibberish. You could be the person that just grabs what you can and runs away. Everyone acts on emotion. Reason is gone.
Christchurch is built on a swamp and ribboned with rivers, springs and streams. The quakes liquefied the land. Wet silt and sand seeped from holes in the ground, first as puddles, then as growing sand volcanoes. Lateral spread (sideways movement) narrowed every bank of every stream. Silt made the waterways shallow. The water table rose as the land subsided. In the eastern seaside suburbs, buildings sank into the silt up to the level of window sills.
The September quakes lifted 0.5 million tonnes of silt, the Boxing day quakes 12 million tonnes, February 13.6 million tonnes. An entire mountain of liquefied land flowed over Christchurch. Near the coast, land was covered in a metre or more of silt.
Our road filled to the depth of half a car tyre. We dug and dug and dug the silt. Wet, the silt is sticky, jelly-like and heavy to move. Dry, it is the finest of dust. It tracks everywhere. We dug until we were exhausted from digging.
Many came to help. One man on a digger saved the day. We met real heroes and felt humbled. Some came to watch. We yelled at real idiots and when it made no difference, ignored them.
Pipes bringing drinking water, stormwater and sewerage were smashed into pieces. Drinking water and stormwater and sewerage poured under homes and into drains, down towards the eastern suburbs. Winter rains flooded entire catchments. Homes filled thigh deep with mud and water and other unmentionables. As autumn arrived, damp homes filled with mushrooms and mould.
By June 2015, 10,000 homes had to be demolished, and by 2016 there were still 2,700 to go. Almost all of the Central city – 1240 buildings – had to be rebuilt.
Christchurch usually throws away 0.5 million tonnes of waste over a 20-year period. By 2015, we had dumped 0.65 million tonnes of waste out of an expected total of 4 million tonnes. 160 years’ worth of waste.
The total repair bill was estimated in 2012 at $40 billion. By 2016, the Earthquake Commission (EQC) and central government promised $16.5 billion, and spent $2.2 billion. The Christchurch City Council ratepayers paid $6.5 billion. That’s a $17 billion gap. The cost was a gross underestimate. 167,000 claims take a long time to resolve. Christchurch will take longer than a generation to recover what it had.