California fault capable of 8.0 earthquake shows movement for first time

• "This is surprising, because we’ve never seen the Garlock fault do anything. Here, all of a sudden, it changed its behavior,” Zachary Ross, lead author of the study, told the Los Angeles Times.
• A significant quake on the Garlock fault could spur strong effects throughout California, including in agricultural and oil-producing regions — as well as military sites.
• It could also destabilize the San Andreas fault, risking extreme shakes and extensive potential damage.

The bottom line: Per the LA Times, "What’s unusual now, Ross said, is that the Garlock fault has been seismically quiet in the historical record until now. And while it’s unclear what the creeping and aftershocks might mean for the near future, the newly recorded movement highlights how much of a potential risk the Garlock fault is to California, should it rupture in a big way."

Go deeper: Number of first responders drops amid growing frequency of natural disasters

• The NHC said at 5pm ET Saturday that gale-force winds would "gradually develop" along the coasts of northeast Florida and Georgia and spread northward to the Carolinas on Sunday.

The big picture: Nestor made landfall on St. Vincent Island, Florida, on Friday as a tropical storm. It spun tornadoes with winds of up to 120 mph, which overturned vehicles, tore off roofs and uprooted trees, per the New York Times.

• Nearly 13,000 customers were without power in Florida at 4:30pm Saturday, according to poweroutage.us. Most of those affected were in Polk County, where an EF-2 tornado "caused a semi truck to overturn onto another vehicle" on I-4 late Friday, ABC News reports.

Go deeper: The Atlantic Basin's tropical storms and hurricanes in 2019

Editor's note: This article has been updated with new details throughout.

Details: Koch and Meir were expected to go for their first spacewalk on Oct. 21, but a power issue on the station forced mission managers to plan Friday's walk first, delaying the Monday spacewalk and others in the series.

• The two astronauts will change out a battery charging unit that collects energy from the station's solar arrays, NASA said in a statement, adding that the unit's failure presents no harm to the orbiting outpost or its astronauts.
• This is Koch's fourth spacewalk and Meir's first, and it is expected to take 5 to 6 hours.
• The two women are self-proclaimed "best friends."

Between the lines: While women made up half of Meir and Koch's 2013 astronaut class, women comprise about 34% of NASA's workforce as a whole, and 23% of the agency's science and engineering employees, according to agency statistics.

Go deeper:

• The future of spacewalks is more robots and less humans
• NASA unveils new spacesuit for the Moon and more
• Watch the spacewalk live, via NASA TV