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The sidewalk is still sinking in SF's Mission Bay. It could liquefy during an earthquake.
By Annie Vainshtein Published 1:24 pm PST, Thursday, January 31, 2019

It's a known problem that the sidewalk around a particular part of Mission Bay is sinking. But the gaps are getting worse.

Dramatic new photos of the sidewalk on 4th street, south of Mission Creek, show a problem that is continuing to deepen around the area, sparking concerns around earthquake safety and daily danger for pedestrians.

One of the reasons for the widening gap is that Mission Bay wasn't built on solid bedrock — it was constructed on artificial landfill. The new development was built atop land once known as Mission Swamp. In an earthquake, this soil can turn to liquid. It's also the exact kind of soil that intensifies ground shaking the most, according to the U.S. Geological Survey.

https://www.sfgate.com/local/article...e-13578335.php