The 1987 stock market crash occurred in October, two months after Greenspan's appointment as Fed chairman. In comparison, Jerome Powell assumed the position less than two months ago.

Alan Greenspan
From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Alan_Greenspan

Alan Greenspan KBE (born March 6, 1926) is an American economist who served as Chairman of the Federal Reserve of the United States from 1987 to 2006. He currently works as a private adviser and provides consulting for firms through his company, Greenspan Associates LLC. First appointed Federal Reserve chairman by President Ronald Reagan in August 1987, he was reappointed at successive four-year intervals until retiring on January 31, 2006, after the second-longest tenure in the position (behind William McChesney Martin).

Jerome Powell
From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Jerome_Powell

Jerome Hayden "Jay" Powell (born February 4, 1953) is a former American investment banker, who is the current Chair of the Federal Reserve.

On November 2, 2017, President Donald Trump nominated Powell to serve as the Chair of the Federal Reserve.

On December 5, 2017, the Senate Banking Committee approved Powell's nomination to be Chair in a 22–1 vote, with Senator Elizabeth Warren casting the lone dissenting vote. His nomination was confirmed by the Senate on January 23, 2018 by a 84–13 vote. Powell assumed office as Chair on February 5, 2018.