"We can hear small noises, but we don't know if they're coming from above or below, from the walls above (crumbling), or someone below calling for help," volunteer rescue worker Dr. Pedro Serrano told the Associated Press.
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Tuesday’s earthquake is the deadliest in Mexico since the 1985 quake, which took place on the same date and left thousands dead.
It is also the second devastating earthquake to hit the region in less than two weeks.
A week and a half ago, a magnitude-8.1 quake killed about 90 people.
Here’s how to help Mexico and those affected by the earthquake:
1. Donate clothes, water and food
If you're nearby the tragedy, donate canned goods to relief or collection centers listed here at Elfinanciero.com.
You can also donate goods to nonprofits on the ground, including the following:
Red Cross Mexico
Save the Children Mexico
La Universidad Nacional Autonoma de Mexico
2. Make a monetary donation
Consider donating to the nonprofits listed above (UNICEF Mexico, Red Cross Mexico, Save the Children Mexico, Oxfam Mexico, La Universidad Nacional Autonoma de Mexico , World Vision, the Global Giving Fund or Project Paz).
Topos Mexico, a Mexican rescue brigade, is also accepting PayPal donations.
Crowdfunding is also on the rise for earthquake relief efforts.
Actress Salma Hayek, who donated $100,000, has launched a fundraiser on Crowdrise to benefit UNICEF.
And GoFundMe also launched a centralized location for verified GoFundMe campaigns to help the victims in Mexico.
3. Use social media to spread awareness
A simple retweet could get the right person where they need to be or the right information where it needs to go.
While you’re on social media, consider retweeting aid accounts or locals to connect them to the appropriate resources.
For example, Topos Mexico has been sharing lists of areas where they need professional medical care.
Locals are also tweeting photos of areas where help is needed. Here, someone calls for help on Twitter for a collapsed building in Coquimbo, where many were trapped.
Some have even tweeted about open hospitals and where victims can receive free treatment, such as the emergency room at Hospital Ángeles Pedregal below.
There is also a Google spreadsheet of rescued individuals that's being shared on social media.
4. If you’re around, volunteer
Mexico City officials have put together a volunteer coordination site, asking those interested to head to the Emergency Rescue Squad (ERUM) building in Chimalpopoca.
But officials warn volunteers to stick to their nearest disaster zones and avoid entering other zones.
Do you have additional tips on ways to help? Let us know in the comments.