It does remind me of reports from earthquakes in the late 1800's and early 1900's in CA.
=====================================================================

Also, according to Edgar Larkin (1906), who collected a great many accounts, the odour of hydrogen sulphide was noted in the area of Sausalito. He also reported that sulfurous odors were pungent in Napa County during the night of the 17th and 18th before the upheaval, and lasted all day. . . . From many of the letters it is clear that the entire region north and east of San Francisco is saturated with gases of sulfur origin. . . .

In Santa Rosa, according to Lawson and others (1908), a strong smell of sulphur had been noticed two days before the earthquake by one Charles Kobes. Since during an earthquake eight years previously, "sulfur fumes came up from under his house which almost drove his family from home", the recurrence of this phenomenon on 16 April 1906 caused Kobes to tell his family that there would be another earthquake.

• Sulpher Odors prior to large EQ's