A brief history of earthquake activity in Australia.
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00:00 (water splashing)
00:02 When the ground shakes,
00:03 it can structurally change the surface of the earth.
00:07 - Melbourne studios are currently shaking.
00:09 We are currently going through an earthquake.
00:11 Our building is-
00:12 - Shit.
00:13 - Whoa.
00:14 - There's an earthquake?
00:14 Holy (beep)
00:17 - Oh, I've never had an earthquake.
00:19 I've never fallen.
00:20 - Australia sits on one stable tectonic plate
00:23 and not on a fault line.
00:24 But every week around 40 tremors hit parts of Australia
00:28 and around 700 reports of tremors are made each year.
00:32 The Australian plate extends
00:34 around the Indonesian archipelago
00:36 through the Southwest Pacific
00:38 into New Zealand and near Antarctica.
00:41 This plate is under pressure
00:43 from the Eurasian plate to the north
00:45 and the Pacific plate to the east.
00:47 Most earthquakes will happen
00:49 at the intersection of these plates,
00:51 but the pressure of plate movements
00:52 can cause interplate fault lines.
00:55 Dr. Seema Musavi, seismologist
00:58 at the Australian National University
01:00 says you can think of Australia as being one big pavlova.
01:04 If you push the sides of this pavlova,
01:06 you'll get cracks anywhere on the top.
01:08 The biggest cracks will be near the sides
01:10 where there's the most pressure,
01:12 but there will also be cracks forming
01:14 around the top as well.
01:16 (machine whirring)
01:25 (people screaming)
01:28 - The landmark cathedral was continuing to collapse
01:32 after the shaking stopped.
01:34 - Earthquakes can occur anywhere in Australia,
01:36 but some regions are more prone to tremors.
01:40 Mountains tend to be a good indication
01:42 on where seismic activity has taken place in the past.
01:45 So Australia's most active earthquake areas
01:48 tend to be around the Adelaide Hills in South Australia,
01:51 the Northern Territory,
01:52 and along the Great Dividing Range
01:54 between Melbourne, Canberra, and Newcastle.
01:57 Australia's largest onshore earthquake
02:00 was a 6.6 magnitude tremor in Tennant Creek,
02:04 which hit on January 22nd, 1988.
02:08 And one of the most fatal earthquakes
02:10 was the Newcastle quake on December 28th, 1989.
02:15 It killed 13 people and caused $4 billion worth of damage
02:20 around the city.
02:22 - Here, right back.
02:24 Get into the car.
02:26 Don't worry about me, I'll follow you.
02:28 - Get those bricks, see if they come off the step.
02:30 - This is Beaumont Street, Hamilton,
02:31 just minutes after the blast or the explosion
02:34 or the earthquake,
02:35 and it looks as though bombs have hit all along here.
02:38 It's like a war scene.
02:39 People are standing around just dazed.
02:41 There has been some loss of life, it appears,
02:44 and buildings all up and down the street
02:46 have just collapsed into the roadway.
02:47 - On average, Western Australia tends to have
02:53 the biggest tremors,
02:54 and is also prone to earthquake swarms.
02:57 An earthquake swarm describes when a cluster of earthquakes
03:00 hit all at once.
03:02 In a normal earthquake event,
03:03 a main quake will occur followed by some aftershocks.
03:07 A swarm can include even hundreds
03:09 of moderately sized tremors altogether,
03:11 often followed by their own individual aftershocks too.
03:15 That's what happened in January, 2022,
03:18 when WA's Great Southern region
03:20 was hit by 40 earthquakes over three weeks,
03:23 including a 4.7 magnitude quake near Wajin.
03:27 During a magnitude one or two quake,
03:31 you might feel some light shaking.
03:34 Damage doesn't tend to occur until the quake hits about 4.5.
03:39 Once the earthquake reaches above five,
03:41 that's when you'd expect to see some damage to buildings.
03:44 But thankfully, in Australia, that is fairly rare.
03:48 (upbeat music)
03:51 (music fades)