1. Dep. of Civil and Environmental Univ. de la Costa Calle 58 #55‐66 Barranquilla Atlántico 080002 Colombia
2. Dep. of Earth Sciences Univ. of Manitoba Winnipeg Manitoba R3T2N2 Canada
3. Dep. of Geosciences Univ. of Texas at Dallas Richardson TX 75080 USA
4. Dep. of Sanitary and Environmental Engineering Federal Univ. of Santa Catarina Florianópolis 88040‐900 Brazil