Boom Goes the Dynamite(?)

According to this piece in the Santa Cruz Sentinel, an investigation by the Federal Aviation Administration (FAA) has come up empty-handed in an attempt to explain the mysterious sonic boom that shook windows in Santa Cruz on Wednesday morning.

Fosco vaguely remembers hearing his windows rattling around 9:15 Wednesday morning, but he was in the middle of snoozebar episode at the time and didn't think much of it (except to wonder why his complex's trash dumpster was being emptied on a Wednesday).

Making the story stranger, however, is the fact that residents in Orange County, CA reported a similar sonic boom exactly twelve hours earlier.

As this article notes, most explanations won't hold water:

• Not an earthquake: "Seismic stations around the Monterey Bay recorded a compression wave at 9:15 a.m. Wednesday, but the wave lacked the up-and-down shear that usually characterizes an earthquake. And, Oppenheimer said, it was moving too slowly to be passing through rock."
  
• Not thunder: "Even if lightning had been present, thunder is only heard over a few miles, Blier said. Reports of the shaking came from cities ringing the Monterey Bay, and seismic monitors in Big Sur picked up the event."
  
• Not aliens: "The National UFO Reporting Center in Washington state received no calls from the Central Coast Wednesday morning."
  
• Not a meteor: "A falling meteor compresses the air below it and creates a vacuum above. That pressure difference could create a sonic boom, but it's more likely to tear the meteor apart in the upper atmosphere. For the sound wave to hit the ground, the meteor would have to be large - and low. 'To have enough energy to create a shock wave to rattle things on the ground, somebody would have had to have seen it,' Giorgini said. 'It probably was not a meteor.'"
  

Which means that it must have been a jet, right? Well, except that:

"We reviewed all the radar data for flights in the airspace in Northern California around the time that people reported this boom," said Ian Gregor, FAA spokesman for the Western-Pacific Region. "There were several military aircraft operating but they were slow. None of these aircraft were going supersonic."

Which seems to suggest that whatever was flying so fast was not a commercial airplane. Nor did it show up on radar, which seems to suggest that we're talking about something military and secret. Fosco can only imagine! But what kind of secret military aircraft would be flying along the California coast twice in twelve hours (near some of the most populated areas in the United States). And why couldn't this jet couldn't be tested farther from the coast (over the open ocean)? Intriguing, no?

All I can hope is that this is some part of protecting CA from North Korean missiles...