A lake formed when an earthquake causes landslides that block a large river.
The threat of flash floods from dams and "quake lakes" formed from landslides blocking rivers has forced tens of thousands of already traumatized quake survivors to relocate, some more than once. The dams also prevented rescue workers from navigating the rivers to reach victims in areas made inaccessible after roads were washed out.
—Barbara Demick, "Dams add to post-quake danger in China." Los Angeles Times, May 28, 2008
The ministry of water warned that 35 "quake lakes", formed when landslides blocked rivers, now endangered survivors. ...
Liu Ning, the ministry's chief engineer, told reporters in Beijing that around 20,000 people have been evacuated from the disaster area due to the flood risk, and another 80,000 might be relocated.
According to a 2004 paper by geologists at the Chinese Academy of Sciences, about 5,500 people were killed after quake lakes burst in the last century.
In 1786, a landslide dam formed by a major quake in Sichuan collapsed 10 days later, killing about 100,000 people.
The ministry also warned that 69 dams in Sichuan were in danger of collapse. The worst-case scenario would be a domino effect, with a flash flood from one quake lake or dam causing lower-lying bodies of water to burst.
—Tania Branigan, "Tremor injures 400 as flood risk grows," The Guardian, May 26, 2008
The temporary lakes created by the earthquake's landslides are far weaker than man-made dams and could give way with little warning, flooding the towns where rescuers search for survivors, a top geologist says.
—Stephen Chen, "Quake lakes are more lethal than dams," South China Morning Post, May 18, 2008
My guess is that the phrase quake lake is older than the May 18, 2008 citation. The second example citation hints that the phrase was used in a 2004 paper, but I can't find that paper. Searching for this phrase is tough because there's a lake near West Yellowstone, Montana called Quake Lake, and it was formed on August 17, 1959, when a quake measuring 7.5 on the Richter scale triggered landslides that blocked the Madison River.