REDDING, Calif. — Authorities believe a wildfire in Northern California was sparked by the exhaust from a truck driven by a man delivering supplies to an illegal marijuana plot.

Freddie Alexander Smoke III, 27, of Sacramento was arrested Saturday for investigation of recklessly causing a fire and illegally cultivating marijuana, according to the California Department of Fire and Forestry Protection.

The fire has burned 6 square miles, or 4,000 acres, of forested land in Shasta County and destroyed 18 structures, CalFire officials said. The fire, burning in steep terrain, was just 15 percent contained Sunday morning.

More than 1,700 firefighters, aided by aircraft, battled the blaze in hot, dry conditions. The fire is threatening 15 homes and about 50 other structures.

NEWPORT BEACH, Calif. — Hundreds of surfers paddled out on boards to remember a Southern California lifeguard who drowned a week ago while saving a swimmer caught in treacherous surf.More than 2,000 people joined the paddle-out tribute Sunday in Newport Beach in memory of 32-year-old lifeguard Ben Carlson. Thousands more watched from the pier and beach.Carlson died a week ago during a rescue after disappearing under 10- to 12-foot waves. He was the first lifeguard to die in the Orange County city known for sandy beaches and waves that attract the attention of surfers worldwide.

GUTHRIE, Okla. — The U.S. Geological Survey has recorded seven small earthquakes shaking central Oklahoma in a span of about 14 hours.Sunday's quakes ranged from magnitude 2.6 to 2.9 and were centered in the Guthrie, Jones and Langston areas, 15 miles to 30 miles northeast of Oklahoma City. The USGS said the quakes were recorded between 7:57 p.m. Saturday and 9:51 a.m. Sunday. No injuries or damage were reported.Those follow four other quakes, including a 4.3-magnitude temblor near Langston recorded shortly after noon Saturday. The other Saturday morning quakes ranged in magnitude from 2.9 to 3.2.Seismologists know that hydraulic fracturing, or fracking — which involves blasting water, sand and chemicals deep into underground rock formations to free oil and gas — can cause microquakes that are rarely strong enough to register on monitoring equipment.However, fracking also generates vast amounts of wastewater, which is pumped into injection wells thousands of feet underground. Scientists wonder whether they could trigger quakes by increasing underground pressures and lubricating faults.Another concern is whether injection well operators could be pumping either too much water into the ground or pumping it at exceedingly high pressures.

NEW YORK — New York City fire officials say six people, including a child, suffered slight burns when a piece of camera equipment caught fire inside the observation deck of 30 Rockefeller Plaza.A fire department spokesman says the fire started just after 7:30 p.m. Sunday and was under control about a half hour later. He says the injuries were caused by embers from the fire falling onto the victims.