The Trans-Mexican Volcanic Belt (TMVB), located in central Mexico, is an area for which low to moderate seismic risk is considered. This is based on the limited instrumental data available, even though large historical earthquakes have damaged some urban centers in the past. However, site effects is an aspect that must be considered in estimating risk, because there are some instances of important amplifications that have been documented with serious effects. In this work, ambient noise and earthquake records from 90 seismic permanent and temporary stations are used to analyze site response in the TMVB. The results obtained show a heterogeneous range in the value of the fundamental frequency. When possible, a comparison was made of the results obtained from ambient noise and earthquake records. In almost all these comparisons, no significant differences were observed in terms of the fundamental frequency. However, there were some stations with a flat average HVSR ambient noise curve that contradicted earthquake data results, which showed peaks at some frequencies. Our results are a first step towards categorizing the different site responses in the TMVB but in order to provide finer details, it is necessary to improve the actual monitoring conditions.

Limes and lemons are grown in 107 countries, in an area of 983,657 hectares, from which more than 15 million tons of fruits were obtained in 2012, which represents 13% of the total citrus fruit produced in the world. Three species of citrus are grown internationally, which due to their acidic taste and the use that consumers give them, mainly in the preparation of soft drinks and dressings for meals, are considered lemons. In Mexico, the production of Mexican lime [Citrus aurantifolia (Christm.) Swingle] is of great economic and social importance. It grows on 81,221.9 hectares distributed in 24 federal entities. Of these, Michoacán, Colima, Oaxaca, and Guerrero with 42,931, 18,996, 6843, and 6856 hectares, respectively, are the most important. The annual production of fruit recorded in 2013 exceeded 1.04 million tons, with a value of 3371 million pesos. The Mexican lime production system generates many jobs practically all year round, both for crop management and in the harvest and processing of fruit. In addition, there are a considerable number of plant-producing nurseries and input-providing companies that benefit from the cultivation of this citrus. This chapter describes the studies on the development and innovation of techniques in Mexican lemon carried out during the last 25 years in Mexico, such as induced mutation and manual hybridization for the generation of new varieties, as well as the use of interstocks and the evaluation of new genotypes with desirable characteristics. On the other hand, propagation and establishment in the field are fundamental points for a good development and production of Mexican lime.