How Islands and Peninsulas are Created- Japan & Tectonics

Many people already make their world maps from continental and oceanic crusts shifting around, which is a great system because it’s actually how it works. But most tectonic maps of constructed worlds that I’ve seen go very large in scale- they have big plates for ocean and for land. But if you look at East Asia, you can see that the boundary of the oceanic and continental crusts are broken up into smaller minor plates. MANY of THE MOST INTERESTING PLACES in the world, East Asia, The Mediterranean, The Caribbean, are interesting because they made of a bunch of MINOR PLATES.
Around the edge of the Pacific is the ring of fire, where the pacific plate subducts underneath the surrounding plates. This means that the pacific plate, being a dense oceanic plate, slides underneath the less dense continental and oceanic crusts to its west. The crust on top gets pushed upwards, and volcanoes are created that build islands. These plate interactions create what we see of East Asia today, the peninsulas, the giant islands, and the small island arcs.
The peninsulas are Korea and Kamchatka, Korea being land that was pulled away from Eurasia as the Amurian plate rotated . As this happened, the land rifted open in the plate’s west, and Lake Baikal was formed. The Kamchatka Peninsula was made by continental crust that was pushed up and built with volcanos from the Pacific’s subduction underneath the continental Okhotsk plate.
The major islands are Japan + Sakhalin, Taiwan, and the Philippines. I… would talk about Indonesia but I don’t know anything about what’s going on here. Japan was basically formed by the Pacific plate subducting under the continental Okhotsk plate, the oceanic Philippine plate subducting under the Okinawa plate, and the Amurian plate subducting under the Okhotsk plate. This complex meeting of plates is why Japan has so many earthquakes and volcanoes. The line along which Japan is formed is easily visible from its shape, going linearly along the Okhotsk plate, and curving to the edge of the Amur plate under which the Philippine plate subducts.
Sakhalin is part of Japan, I think. At least in the island chain. This is the real Japan. During the last glacial period, it looked like this- Honshu being a peninsula connected to Korea, and Hokkaido and Sakhalin being peninsulas off of Russia. This points out that if you’re unsatisfied with what your map looks like, you can always play around with its sea level, or switch your big islands to peninsulas and vice versa. These can make for a more natural and less artificial looking landmasses.
Taiwan was made by the oceanic philippine plate subducting under the continental Yangtze plate. During glacial periods, it was attached to mainland Asia.
The Philippines are created on a belt that sits between the Sunda and Philippine plates. Both of these plates subduct underneath this belt to create the islands. It’s a super complex convergent boundary… I’m taking a geology class this semester, I’ll tell you how it really works then.
The islands in between the Philippines and Taiwan are part of the Luzon Volcanic arc, made by the Philippine plate subducting underneath the belt that the Philippines sit on.
The Ryukyu Islands between Taiwan and Japan were created by the Philippine plate subducting underneath the tiny Okinawa plate. On the other side of the Philippines plate, the Pacific plate subducts underneath it to create the Mariana Islands, ending at Guam.
Coming off of Hokkaido on the eastern edge of the Okhotsk plate are the Kuril Islands, where the Pacific subducts and forms volcanic mountains.
And all the way up north, the pacific plate subducts underneath the continental North American plate to create the Aleutian islands and Alaska Peninsula.
Given all of this, I think that we can reasonably make a rule that may be a bit geologically dubious, but in effect works for world building. On the minor and micro tectonic plates where major continental and oceanic crusts meet, landforms such as peninsulas, and big and small island chains will be created. These will form either along the side of a plate, or at the intersection of the plates. The more plates there are meeting in one place, the more certain that there’ll be a landform there.
But remember! Your world building does not serve the scientific models. Here, plate tectonics only exist as a tool to make realistic and good looking landmasses. You can always creatively override the science!
All of this is to say that around the coast of East Asia, there is a multilayered string of islands between the Pacific plate and the Eurasian mainland.

Some changes made for intervals in video

[allanjohnson]

Finally someone is talking about the small scale stuff! It's like, the only reason to do tectonic simulations for map-making.

[Stoneworks]

おまえ わ もう しんでいる


何?!




Program used at the end is Wonderdraft, it's really good for easy decent looking maps -but it's 30$

[droopsmoop]

Wow, I never knew that the Philippine Plate was just a bunch of crustal blocks and arcs together in a trenchcoat

[JontyLevine]

Just for once, I'd like to see an in-universe fantasy map (such as the one you did at the end there) that looks _nothing_ like the actual landforms, like how when cartographers explored the new world and got the shape of North America ENTIRELY wrong. Also make one of the islands super-thicc for no reason except that the cartographers didn't know its true size and needed the king to fund another expedition, and so erred on the side of caution because kings love a thicc island ;) (I can't believe I've just used the word thicc twice now). Also remember how people thought for a long time there was as much land in the southern hemisphere as there was in the north and Terra Australis never lived up to the hype? Yeah.

If you want to be an evil DM, you can _only_ show players your in-universe map, and keep the more accurate one to yourself.

[AiwassArchive]

Protip - you can also create volcanic islands from volcanic hotspots such as Hawaii. this can be used for oceanic islands that are not near a plate boundary.

[Slva]

dude i hope you keep doing the demo's at the end. Also like the way you incorporated the info from the Skyrim map into it while laying out the tectonic plates. Looking forward to your next one man.

[kartoffsun]

Japan is and island by the sea filled with volcanoes and it's *BEAUTIFUL* !

[srjskam]

Protip: when you've finished with your notSoutheastAsia, notMediterranean or notCaribbean, rotate your map 180° to make it less obvious...

[mimikal]

12:15

I will finally find out what happens in the Sam o'nella intro music after the fade out!

[tasogarerubica]

This is something I found out through a japanese documentary on the formation of the Japanese Archipelago and it was a while ago, so please excuse my hazey explanation. The honshu island, was formed by it detaching from the main Eurasian continent probably due to the Amurian plate turing, like how the korean peninsula was formed. in the documentary it described the movement like a door opening creating two strips of islands. The interesting part is that this leaves a gap in between the kyushu area and the touhoku area, now this are was filled with land mass through a bombardment of by island arc of the Izu and Bonin island arc over long periods of time. This was honestly the most intriguing part of the documentary, finding out that Japan an Island arc itself was machine gunned by another island arc.

[bigwillblue]

I'd like to see you make a video on metallurgy and mining in relation to world building.

[imborahey]

Looks like one of those old-timey European maps of anything not on the Mediterranean lol, love it

[gauracappelletti]

this video is great because it actually shows a good way to USE the information instead of just being a geography lesson

[adamguthrey]

What was the program you used at the end to make the map?

[starsixseven]

Never make an intro. How you begin your videos now is perfect.

[Weirdoid]

I know other ways for island and peninsulas forming also exist. Sediments carried by current, mid ocean hot spots, continental glacial deposits, etc.

[idee]

brilliantly presented that is easy to understand.

[alextrollip]

The photoshop map looked OK to my eye.
Then you did the wonder draft map and man it was so clean. That's some quality map making.
Now I just need to somehow remember all the things you mentioned.

[PlayNowWorkLater]

I’m blown away by what you do here. I’m not really a gamer. I enjoy the odd game here and there. But I do really enjoy a good story, and also I am a man of science. Mostly geology, astronomy and physics. I love how this channel combines science (how the world really works, and all the underlying rules that make it so) with telling a good story. Ie video games do well when it’s believable. I think character development and story arc are important in a video game, but having a realistic world for those characters is key. I’m really seeing that with this channel. I feel like I’m looking behind the curtain at the castle of the great Oz. Seeing what goes into making a world believable. Very cool! I just stumbled on this channel, because I’m doing a deep dive in Geology/plate tectonics and the algorithm suggested this. Pleasantly surprised am I.

[gone]

why is this unlisted it's top-notch and should be put alongside your other videos