Officials found that out when they tested the soil prior to a construction project.
"The initial tests showed us that the soil under Lum Elementary School could be susceptible to significant liquefaction," said Susan Davis, with the Alameda Unified School District.
This Alameda school sits on soil that could liquify in a major quake. Will it have to close? On ABC7 News. pic.twitter.com/XiNxBdpvAX— Eric Thomas (@ericthomaskgo) April 27, 2017
The dirt is a mixture of native soils and fill. That's what makes it so susceptible to liquefaction.
Liquefaction occurred in San Francisco's Marina District during the 1989 Loma Prieta earthquake where loose soil amplified the quake's energy and caused massive destruction.
Fearing something similar could happen here, officials are considering a range of options including closing the school at the end of the school year. They're also hoping that no major quake hits in the next 5 or 6 weeks.
RELATED: Bay Area earthquake tracker
"We have the capacity at our other elementary schools to take Lum students and Lum teachers," said Davis.
"Anytime there's anything related to safety and children there's a sense of panic," said Brina Siv, a parent.
Parents were notified this week of the problem at Lum Elementary.
"It's very shocking but I know they're going to take care of it and deal with it okay," said Meliza Surdi, a parent.
"We just want to know as a community that every possibility is being looked at," another parent told ABC7 News.
School officials say they are looking at other options, including retrofit or building a new school. But, both those would be expensive, and kids would have to be taught elsewhere in the meantime. They plan to further update parents at a school board meeting Friday.