Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Geography
5 Dec 2025
255
5 pages
M @iamjungkook
Tectonic hazards like earthquakes and volcanic eruptions can be absolute disasters, but scientists have clever ways to measure... Show more
Ever wondered how scientists actually measure the power of earthquakes and volcanic eruptions? There are three key scales you need to know about.
The Mercalli Scale measures what people actually experience during an earthquake - from simply waking you up to completely destroying buildings. It's called a relative scale because the shaking feels different depending on where you are.
The Moment Magnitude Scale (MMS) is what modern scientists prefer because it measures the actual energy released. It calculates this using how much the fault slipped, the affected area, and how rigid the Earth is in that spot.
For volcanoes, there's the Volcanic Explosivity Index (VEI). This measures how explosive an eruption is by looking at how much stuff gets thrown out, how high the ash cloud goes, and what observers actually see happening.
Remember Both MMS and VEI are logarithmic scales - each number up means ten times more powerful!
Hazard profiles are basically report cards that help governments decide which disasters deserve the most money and attention. They're brilliant for ranking threats and making smart decisions about where to focus resources.
The tricky bit? Comparing similar events (like two earthquakes) is dead easy because they use the same measurements and cause similar damage patterns.
But comparing completely different hazards - like earthquakes versus volcanic eruptions - gets properly complicated. Each disaster type affects society differently and happens at different scales and timeframes.
Key Point Some important details often get missed or simplified when trying to squeeze different hazard types onto one comparison scale.
Magnitude tells you the raw power - Richter Scale for earthquakes, VEI for volcanoes. Generally, bigger magnitude equals bigger disaster, though it's not always that straightforward.
Speed of onset varies massively - earthquakes hit instantly whilst shield volcanoes can take ages to properly get going. This timing is crucial for evacuation plans, especially if you're worried about tsunamis following earthquakes.
Areal extent shows how much ground gets affected. The 2004 Asian tsunami covered multiple countries, whilst some earthquakes only damage a few kilometres. Volcanic gas emissions can go global, but earthquake shaking stays relatively local.
Think about it An event covering a huge area will likely affect way more people and countries.
Duration ranges from minutes (earthquakes) to months (major volcanic eruptions). Longer events generally cause more damage because they have more time to wreck everything in their path.
Frequency varies wildly - minor earthquakes might happen every few years, whilst major ones could be centuries apart. More frequent events often mean better disaster planning, like in Christchurch where regular earthquakes led to improved preparations.
Spatial predictability asks can we predict where this will happen? Volcanoes are fairly predictable since they occur at known volcanic sites. Earthquakes along fault lines are trickier to pin down to specific locations.
Pro tip Areas with frequent hazards often develop better emergency responses through experience.
Here's something that might surprise you - developed countries actually suffer greater economic impacts. Their fancy infrastructure costs way more to rebuild when disasters strike. Chile spent £30 billion rebuilding after their earthquake.
But developing countries get hammered with worse social impacts. Without money for earthquake-proof buildings or early warning systems, more people die and get injured. Haiti's earthquake affected 3.5 million people compared to Chile's 2 million.
Environmental impacts hit everyone equally hard though - ecosystems get destroyed, forests burn in pyroclastic flows, and droughts wipe out agriculture regardless of a country's wealth.
Reality check Money can't prevent natural disasters, but it dramatically changes who survives them.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the critical concepts of natural hazards in this comprehensive PowerPoint presentation. Covering key topics such as climate change, earthquakes, volcanic activity, and tropical storms, this resource includes detailed case studies on the Somerset Levels, Typhoon Haiyan, and the Haiti earthquake. Ideal for GCSE Geography students seeking to understand the dynamics of hazardous earth processes and their impacts.
GeographyQuotes from every main character
English LiteratureApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
M
@iamjungkook
Tectonic hazards like earthquakes and volcanic eruptions can be absolute disasters, but scientists have clever ways to measure and compare them. Understanding these measurement scales and hazard characteristics helps predict impacts and prepare communities for the worst-case scenarios.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered how scientists actually measure the power of earthquakes and volcanic eruptions? There are three key scales you need to know about.
The Mercalli Scale measures what people actually experience during an earthquake - from simply waking you up to completely destroying buildings. It's called a relative scale because the shaking feels different depending on where you are.
The Moment Magnitude Scale (MMS) is what modern scientists prefer because it measures the actual energy released. It calculates this using how much the fault slipped, the affected area, and how rigid the Earth is in that spot.
For volcanoes, there's the Volcanic Explosivity Index (VEI). This measures how explosive an eruption is by looking at how much stuff gets thrown out, how high the ash cloud goes, and what observers actually see happening.
Remember: Both MMS and VEI are logarithmic scales - each number up means ten times more powerful!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Hazard profiles are basically report cards that help governments decide which disasters deserve the most money and attention. They're brilliant for ranking threats and making smart decisions about where to focus resources.
The tricky bit? Comparing similar events (like two earthquakes) is dead easy because they use the same measurements and cause similar damage patterns.
But comparing completely different hazards - like earthquakes versus volcanic eruptions - gets properly complicated. Each disaster type affects society differently and happens at different scales and timeframes.
Key Point: Some important details often get missed or simplified when trying to squeeze different hazard types onto one comparison scale.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Magnitude tells you the raw power - Richter Scale for earthquakes, VEI for volcanoes. Generally, bigger magnitude equals bigger disaster, though it's not always that straightforward.
Speed of onset varies massively - earthquakes hit instantly whilst shield volcanoes can take ages to properly get going. This timing is crucial for evacuation plans, especially if you're worried about tsunamis following earthquakes.
Areal extent shows how much ground gets affected. The 2004 Asian tsunami covered multiple countries, whilst some earthquakes only damage a few kilometres. Volcanic gas emissions can go global, but earthquake shaking stays relatively local.
Think about it: An event covering a huge area will likely affect way more people and countries.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Duration ranges from minutes (earthquakes) to months (major volcanic eruptions). Longer events generally cause more damage because they have more time to wreck everything in their path.
Frequency varies wildly - minor earthquakes might happen every few years, whilst major ones could be centuries apart. More frequent events often mean better disaster planning, like in Christchurch where regular earthquakes led to improved preparations.
Spatial predictability asks: can we predict where this will happen? Volcanoes are fairly predictable since they occur at known volcanic sites. Earthquakes along fault lines are trickier to pin down to specific locations.
Pro tip: Areas with frequent hazards often develop better emergency responses through experience.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Here's something that might surprise you - developed countries actually suffer greater economic impacts. Their fancy infrastructure costs way more to rebuild when disasters strike. Chile spent £30 billion rebuilding after their earthquake.
But developing countries get hammered with worse social impacts. Without money for earthquake-proof buildings or early warning systems, more people die and get injured. Haiti's earthquake affected 3.5 million people compared to Chile's 2 million.
Environmental impacts hit everyone equally hard though - ecosystems get destroyed, forests burn in pyroclastic flows, and droughts wipe out agriculture regardless of a country's wealth.
Reality check: Money can't prevent natural disasters, but it dramatically changes who survives them.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the critical concepts of natural hazards in this comprehensive PowerPoint presentation. Covering key topics such as climate change, earthquakes, volcanic activity, and tropical storms, this resource includes detailed case studies on the Somerset Levels, Typhoon Haiyan, and the Haiti earthquake. Ideal for GCSE Geography students seeking to understand the dynamics of hazardous earth processes and their impacts.
GeographyQuotes from every main character
English LiteratureApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology