I asked in main meta help to do a SEDE query for questions, answers and upvotes in the history of Earth Science Stack Exchange since its start in 2014.
Here you can check the query for questions, answers, average votes, upvotes and downvotes done by user rene (all datasets are updated each month).
Analysis
I modified the SQL sentences to make a query about questions and answers. I added the tendency lines.
I guess at the beginning some questions were stored and progressively liberated, but I am not sure how a site starts.
Then we had between 2014 and 2020 an increasing tendency.
At the end of 2019 we have a pick of answers. I associate this with too events. One is surely that we started to appear firsts for searches as "help identify my rock" in Google and the world is many people trying to know what rock they found in the field. The other is user Michael Walsby was giving non sourced wrong opinions in every question he saw in the forum. The drop came when we banned those low quality questions and we deleted all the questions solving the issue, and when moderators suspended Walsby account in March 2020.
Then the tendency continued being a bit positive. That's good.
I did another query for only upvotes to see if I could infer more analysis:
We have a decreasing tendency and something that breaks the general tendency between 2018 and mid 2020. That something is the id-my-rocks questions we started to receive massively in 2018 after appearing in Google searches.
The general tendency is a site health problem. It should be related with a decrease in the number of quality answers and with the loss of active users also voting. Both are a sign of loss in active experts. That's bad.
I did another query for comments
Comments have a positive tendency until the beginning of 2020, when we banned id-my-rock questions and user Michael Walsby was suspended. That's good too. They have a peak related to the discussions and then drop.
Then the tendency is not clear and it would be too risky in my opinion to make an analysis.
Conclusions
In my opinion, for the next years our biggest challenge is to attract and keep the loyalty of more experts.
If we want to keep the loyalty askers, we need, if possible, to give more than one answer or two to a good question and upvote the question strongly to try to encourage the poster not to leave the site once his query is solved.
I will use a quote of World Chess Champion Emmanuel Lasker to encourage people to post complementary answers:
“When you see a good move, look for a better one.”
To loyalty experts, we should not forget to reward those who answer for their time, to encourage them to stay on the site and go for the moderation privileges.
I encourage also people to talk to your partners about the site and to put a link if you have a site about Earth Sciences.