A thundering crash, which sounded like the roof collapsing, jolted us out of bed Tuesday night.  We found the source of the boom, an 11-pound, ebony, carved African mask that had fallen from the top shelf of a closet onto the hardwood floor, gouging out holes, one as deep as a half inch.  Earthquake?  That was the only explanation we could imagine.  Yet we’ve been in earthquakes before, seen the swaying of the lamps, felt the rumbling underfoot, heard the rattling of the window glass, and experienced a temporary disorientation; however, we didn’t notice any of these signs before or during the mask’s downward plunge.  

We wouldn’t have to wait until morning to learn from the news media whether there were any seismic happenings in our area. We could make a quick check ourselves because our house is an official seismic monitoring station.  Last summer a crew from the Pacific Northwest Seismic Network installed a small seismograph in our garage and attached a router to our computer.  We can check earthquake activity in this area any time.  What we found when we checked were the three recordings above, covering the hours between 15:41:50 and 15:43:40.  If you look at the bottom graph you can see the biggest blip on the far right.  According to the U.S. Geological Survey, an earthquake occurred in the Seattle Tacoma Urban Area, magnitude 2.0, at a depth of 15 miles, at 15:42:36 hours.  Our station, which obviously was doing its job, is located about 20 kilometers from the epicenter. We decided that this quake must have jolted the African mask close to the edge of the shelf and something later in the day, perhaps a jet flying low overhead, had caused it to fall.

Finding a scientific explanation was helpful in quelling my husband’s fears that the spirits embodied in the mask were angry.  However, we’re taking no chances of a future crash. This mask will have to live at sea level, or perhaps below.