. >> abc news reporter leann melendez has more on what caused the smog. >> reporter: visitors to san francisco's twin peaks were not battered by the traditional wind and fog. instead, people were marvelling at the hazy skies u.n. usual for this area. smoke from more than a dozen fires in northern california and oregon has been moving towards the bay area and staying here because there hasn't been a wind system to push it out. >> we've not had fresh wind, not had a lot of ventilation, so high heat, low wind, we're breathing in smoke and ozone. >> reporter: add the vent high temperatures and the air quality becomes extremely poor. >> typically patients who are normally well controlled with their inhalers and their medications now are finding that those aren't working like they used to. >> reporter: patients also complain of headaches and coughing with all those particles in the air, doctors recommend not exercising outdoors. >> i wasn't running it when it was 106 for sure, i was inside just waiting for things to cool down. >> reporter: conditions were slowly changing, enough to lift th

leann melendez, abc 7 news. >>> developer is taking traffic action on a $20 million housing project inhe east bay. >> dan is here with a preview of his report tonight on abc news at 11. >> when tip came in i was began researching and able to confirm crews under -- they dug up the first one more than two years ago. several people who bought homes in freemont tell me the builder did not disclose what they found and how they're going to dispose of the remains. the company had a duty. >> if there are defects or problems with the property that could not be found through that reasonable diligence, the seller has the obligation to make that disclosure to the buyer because the seller has a greater position of knowledge. >> tonight i'll explain what builder is now offering to people who bought homes there, and i'll tell you what will happen to those remains. some 650 years ago. that's tonight on abc 7 news at 11:00. >>> coming up next, a first for fremont. plans to turn a old motel into affordable housing. >>> temperatures and fire danger on the rise. a closer look in the forecast coming up. >>

leann melendez, abc 7 news. >>> developer is taking traffic action on a $20 million housing project inhe east bay. >> dan is here with a preview of his report tonight on abc news at 11. >> when tip came in i was began researching and able to confirm crews under -- they dug up the first one more than two years ago. several people who bought homes in freemont tell me the builder did not disclose what they found and how they're going to dispose of the remains. the company had a duty. >> if there are defects or problems with the property that could not be found through that reasonable diligence, the seller has the obligation to make that disclosure to the buyer because the seller has a greater position of knowledge. >> tonight i'll explain what builder is now offering to people who bought homes there, and i'll tell you what will happen to those remains. some 650 years ago. that's tonight on abc 7 news at 11:00. >>> coming up next, a first for fremont. plans to turn a old motel into affordable housing. >>> temperatures and fire danger on the rise. a closer look in the forecast coming up. >>

. >> in san francisco, leanne melendez, abc 7 news. >> central mexico has endured 19 earthquakes of 6.5 or stronger in the last century. there are two faults that run into each other causing large plates to break apart. another issue is sedimentary basins. they are underground pockets created by tectonic activity that fill with sediment. central mexico as well as the bay area have many of these areas. >> mexico city is a large valley that has soft sediment in it, and so when the seismic waves from this earthquake come into that region, they tend to be amplified. >> the usgs says today's earthquake appears to be unrelated to a magnitude 8.1 quake that hit mexico's southern coast on september 7th just a few days ago. >>> today's earthquake happened 32 years to the day as matt pointed out that an 8.0 quake hit mexico. at least 5,000 lives were lost then. abc 7 news reported from mexico for a week with updates from now retired abc 7 news reporter rico chacon. decades after his coverage he still vividly remembers moments that changed his life. >> this one lady holding a rose as if to hold on