The recommended chart is the inauguration of King Juan Carlos on Nov. 22, 1975 at 12:45pm CET, Madrid, Spain. Scorpio sun, aquarius asc. I have no idea if there is a reason to use that one instead of the current king. It’s an old article though.
There is [also this article](https://www.astrologyweekly.com/countries/spain.php)– but I can’t vouch for this site, as I’m not familiar with it. It suggests a 1479 chart for the creation of Spain (when Juan II of Aragon died), set for January 19th at 7:00 am in Madrid.
If you have a particular city in mind, and if it’s large enough, there might be a city chart at astrodatabank. Just search at [astrodatabank.com](https://astrodatabank.com).
Otherwise, it’s possible some in the Mundane Astrology field have written about this, since it seems unusual. There are Mundane Astrologers who specialize in weather and natural earth events, etc. Try googling with the words *spain earthquakes “mundane astrology”* and then the year of the event/s. Be sure to put “mundane astrology” in quotes, so you will get better results. Try variants such as “mundane astrologer” in stead of astrology. Also, try leaving out the word mundane, if you don’t get much. You could also google just the words *astrology earthquakes* and see what that gets you.