If you don't know about it, then https://misskey.io/ is an extremely good Twitter alternative that is almost exclusively used by Japanese people. A lot of Japanese artists and others are eager to make the switch from Twitter too.

Also, Twitter isn't the best place to confirm if there is an earthquake anymore, since the website is completely private if you don't have an account. I use https://unnerv.jp/about/more instead now, since it's on Mastodon and can interop with misskey and other fediverse software easily.