During the Depression foreclosure rates skyrocketed. What was the main cause?

In 1929, The US entered a depression. It was accompanied with a stock market crash, but there was, or there should have been nothing remarkable about this. Market crashes occurred regularly and were an unavoidable fact of life. There was still something unique, something brewing. The Federal Reserve system created after the great 1907 market crash, one more, but one that left its mark on the course of events. Because unlike all the preceding market collapse, this one was averted. By J.P. Morgan. The man simply loaned to the nation, and saved the day. Washington DC had issues with this.

Few governments sleep well when they owe their survival to an individual who knew more, faster, and better. In the eyes of the public, government had gone fishing that day. Six years later they were ready for the next 1907 crash. They did not understand the impact of stocks, or more precisely, that of the drastic and swift adoption of a new theory about stock investing. It said that one could invest in stocks. That was new to the world of investors who only knew the B word, Bonds. Stock trading reflects valuation, but mostly hope.

The present value of all discounted future earnings, such was the definition of stock value. Now stocks are great if you don't need them right now. If you do, their value resides in their ability to turn into cash. Liquidity, how fast can paper certificate be turned into real money, is what matters. That is all known. But if you look at a dollar bill, you will see that there are more words on a bill, than Gold in it. So you're back to square one. If you trust what you read, that the government will honor its promise. If you don't, it's back to square zero.

The rest of my answer can be read here https://socratic.org/scratchpad/2962c806ddf128c2b5b7