In only 24 hours, a very small section of Taiwan was struck by 22 magnitude 5 earthquakes and 21 magnitude 4 earthquakes in what was an unusually intense earthquake swarm. But, why exactly did this occur? While these events could technically be classified as aftershocks, they occurred in a palindrome like increase before and decrease after two magnitude 6 earthquakes struck.

Thumbnail Photo Credit: This work "2024TaiwanQuake4a", is a derivative of a photo (cropped, resized, text overlay, overlaid with GeologyHub made graphics (the image border & the GeologyHub logo), from "04.03 副總統前往花蓮瞭解災害情形及救援進度", by: Shufu Liu, 總統府, presidentialoffice, 2024, Posted on Flickr, Flickr account link: https://flickr.com/photos/presidentialoffice/, Photo link: https://flickr.com/photos/presidentialoffice/53629524420, CC BY 2.0. "2024TaiwanQuake4a" is used & licensed under CC BY 2.0 by YouTube.com/GeologyHub

Note: This video's thumbnail image displays damage from the larger April 3rd magnitude 7.4 earthquake rather than the 31 magnitude 5 and 2 magnitude 6 earthquakes mentioned in today's video.

A special thanks to the EarthquakeSim YouTube channel for granting me permission to use clips of his footage!
Video Sources from the EarthquakeSim YouTube channel:
[1] https://www.youtube.com/watch?v=W6CaiyNsL1Y
[2] https://www.youtube.com/watch?v=RLCEDINUFao
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Google Earth imagery used in this video: ©Google & Data Providers

This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at tccatron@email.asu.edu and I will make the necessary changes.

Various licenses used in sections of this video (not the entire video, this video as a whole does not completely fall under one of these licenses) and/or in this video's thumbnail image (and this list does not include every license used in this video and/or thumbnail image):
CC BY 2.0: https://creativecommons.org/licenses/by/2.0/legalcode
CC BY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode

Sources/Citations:
[1] Huang, HH., Wang, Y. Seismogenic structure beneath the northern Longitudinal Valley revealed by the 2018–2021 Hualien earthquake sequences and 3-D velocity model. TAO 33, 17 (2022). https://doi.org/10.1007/s44195-022-00017-z. CC BY 4.0.
[2] U.S. Geological Survey

0:00 Taiwan Earthquake Swarm
0:48 Earthquake Distribution
2:12 Foreshocks
3:14 Earthquake Swarm Cause