As Mexico's first lady and the U.S. ambassador to the country were speaking there early last month, David Suro felt and heard the rumbling of the nearby Popocatépetl Volcano.

Suro, owner of Tequilas restaurant in Center City, was on his foundation's third annual trip to the town of San Mateo Ozolco in the Mexican state of Puebla, from where many Mexican immigrants who live in South Philly hail.

He asked a student who attended about the noise, and she replied: "Don't worry. We are a town of good people."

Suro, founder of the Siembra Azul Foundation, had brought Philadelphia's first lady, Lisa Nutter, to San Mateo on the foundation's first trip in June 2010. And on each trip to Mexico, the group met with Mexico's first lady, Margarita Zavala, the wife of President Felipe Calderón.

These high-level contacts have benefited San Mateo, now considered a ghost town because such a high proportion of its working adults have come to Philadelphia to find jobs, leaving behind primarily the young and the old. Observers estimate that a third to half of San Mateo Ozolco's population, or about a couple of thousand people, now live in Philadelphia.

The Siembra Azul Foundation seeks to improve the lives of Mexican immigrants in Philadelphia in the areas of health and education, and to help improve the lives of people in San Mateo.

Suro, 51, would like to see migration from Mexico to Philadelphia decrease because the "social cost of losing people in Mexico is pretty high." On the foundation's most recent trip, he talked with some kids about the negative effects of migration. "What are the consequences for the town? ... I am concerned about how the young kids are able to sustain the economy of the town," he said. "A lot of kids also don't have parents."

A native of Guadalajara in Mexico's central-western state of Jalisco, Suro came to Philadelphia in 1985 after meeting his wife, Annette — a Philly native with whom he is now separated — in Cancun.

He established the Siembra Azul Foundation about five years ago. The foundation, working with other organizations, has offered English classes to Mexican immigrants here. It has also donated money to Puentes de Salud, a free health clinic for Latino immigrants in Philadelphia.

Other key people who have gone on the annual San Mateo trips are Steven Larson, 52, an emergency-medicine physician at the Hospital of the University of Pennsylvania and co-founder of Puentes de Salud, and Nora Hiriart Litz, a Philadelphia artist, teacher and Mexico City native.

Having Lisa Nutter on the first trip was a bonus.

Suro invited her because she is Philadelphia's first lady and because of her background in education. Nutter is president of Philadelphia Academies, a nonprofit that helps city school students prepare for jobs and careers.

"The highlight of the trip for me was meeting with middle- and high-school students and talking with them," Nutter said by email.

"The thing that struck me most was hearing them speak about the separation from family," she wrote. "Some of the young people I met have older siblings in Philadelphia and they talked about how much they missed having their families together.

"That's something we have to think about in the school setting; how the breakup in these relationships impacts kids."

Suro said the first trip to San Mateo had a "snowball effect." After visiting the small, rural town and speaking with its mayor, students and teachers, the group met with Zavala at the presidential residence in Mexico City.

Getting Zavala interested in the links between Philadelphia and San Mateo has helped put San Mateo "on the radar of organizations like Save the Children" and HSBC, the global banking company, said Suro.

Through that connection, HSBC Mexico helped to fund a renovation of San Mateo's elementary school, an expansion of its high school and the building of its new sports facility, fruits of which the group saw on its most recent trip.

This year, the group flew to Mexico City on May 6, then two days later drove the two hours to San Mateo. There, they met Zavala, U.S. Ambassador to Mexico Anthony Wayne, the first lady of Puebla state, and representatives of HSBC and Save the Children. They toured the new school facilities and spoke with students about their family members in Philadelphia.

They saw the gigantic, beautiful murals that Hiriart Litz organized and helped to paint with students, teachers and community members on the high-school walls. The murals include words that reflect the plight of migrant workers who have left Mexico and their families behind.

One saying, when translated into English, reads: "Here [In the United States] I am like a bird that cannot leave her cage to extend her wings.

"There [In Mexico] I am like a hummingbird, so small but the size does not matter, for it can open its wings and fly higher than the sky."