On Thursday Seattle Parks and Recreation fenced off Waterfront Park between Miners Landing and the Seattle Aquarium to investigate some apparent "instability" in the area.

A spokesperson for Seattle Parks said a waterline break near Pier 58 initially drew them to the area. Once crews showed up, they noticed "a need to assess the stability of the Pier and adjoining uplands."

"Until engineers get in there and assess the situation, they can't exactly say what's going on," the spokesperson said. No word on how long that assessment is scheduled to take.

In a Tweet, the department said, "There is some kind of decay in places; the assessment is to gauge what that means for stability and safety." They also said "[Miners Landing] and the aquarium are not affected by this."

The "decay" seems to have formed between the park and the seawall, which the city finished rebuilding in 2017. The new wall, which ran over budget, was built to better withstand earthquakes.

Update 9:39 p.m.: According to a surpassingly florid blog post published sometime today—I see no timestamp, and register no press release in my inbox—the Parks department says the pier has "shifted by several inches" toward Elliott Bay, "creating a visible gap between the Pier and the adjacent upland."

The department assures us that the pier is not suddenly deciding to throw itself into the Bay because it has just learned Jenny Durkan is mayor. "It is normal for piers to shift with tides, and to shift over the years," spokesperson Kyle Morrison writes. "This shifting of the Pier has been an ongoing but manageable maintenance issue over time that has happened well within the bounds of public safety...The discovery on August 5th, however, was an acceleration of what had been observed in times past."

Morrison said a "secure metal plate has safely spanned the existing gap between the two separate and independent pieces of infrastructure and retrofitted as needed over time."

Engineers will complete a report in the next week to explain "the extent of the shift, the state of the pier, and the likelihood that the shift will continue and at what rate."

Parks planned to replace Pier 58 in 2022, and they've already been working on the designs. They might have to step up that work here pretty soon.

Here's a few more pics of the cracks. Armchair engineers feel free to go off in the comments: