a) Major hazards and historic disasters
Baja California is located at the Northwest (NW) extreme of Mexico in the northern part of the Peninsula
of Baja California. It is one of the 31 states of the Republic of Mexico, with a total area of around 71,800
km²; and a population of 3.1 million (2009). It is divided into five municipalities: Mexicali, Ensenada,
Tijuana, Tecate, and Rosarito.
Baja California is exposed to various hazards such as earthquakes, floods, landslides, droughts, and
Santa Ana winds accompanied by wildfires, which have caused major or disastrous damage and losses
to the state throughout its history.
Earthquakes are the main hazard in Baja California. Historic seismicity shows that moderate and severe
earthquakes, with magnitudes 6 or above, have taken place in Baja California, especially in the area of
and around Mexicali, most probably due to its closeness to the San Andreas fault system. The figure
shows the seismic activity in the last 50 years including the location of the identified active faults and the
State's main urban areas.
Figure 1. Seismic epicentral distribution with magnitude ≥3.0, reported by
RESNOM (CICESE) for Mexican territory and Caltech for U.S.A. territory
from 1793 to October 2010
Mexicali has experienced 5 disastrous earthquakes between 1927 and 2010. The last earthquake, in April
2010, left losses in rural and urban areas of Mexicali amounting to 427 million dollars, according to
government information. A year and a half after the earthquake, the city is still recovering
Flood is the second most important hazard in Baja California. They result from the combination of intense
precipitations, insufficient drainage capacity in urban areas and the topographic and geological
characteristics of the region. The table shows the most important flood events in the State.
Table 1. Historic floods have impacted Baja California.
No.
1
Date
1874
City
Tijuana
2
3
4
5
6
7
8
9
10
11
12
1891
1906
1916
1978
1980
1982-1983
1992-1993
1997-1998
2001
2004
2008
Tijuana
Mexicali
Tijuana
Ensenada
Tijuana-Ensenada
Tijuana
Tijuana
Tijuana
Mexicali
Ensenada
Playas de Rosarito
Tijuana is the city most affected by floods. Since its foundation, about 100 years ago, eight devastating
floods have considerably affected the city’s population and economy. Ensenada is the second city of the
State most affected by floods, followed by Mexicali and Rosarito.
Landslides in Baja California are mainly caused by unplanned urban growth on unstable slopes. Tijuana
is the city most affected by landslides with at least six major recorded landslides that damaged houses,
aqueducts and roads.
Drought is one of the most important hazards in Baja California with a broad range of impacts. It is,
however, a very little understood phenomenon and there is no comprehensive data or information of its
effects.
The Santa Ana winds occur during the fall and winter. They are mainly characterized by dry winds from
the Northeast that generate dust/sand storms (figure 2a) and spread wildfires (figure 2b) affecting the
whole State. Wildfires destroy grazing fields significantly affecting the State’s economy, whose main
activity is livestock.
a)
b)
Figure 2. a) Dust transported to the ocean during a Santa Ana Condition, February 9 to 11, 2002, is shown in an
image provided by the National Aeronautic and Space Administration (NASA) Project: SeaWifFS (Ortiz
Figueroa, 2009). b) Smoke from southern California wildfires is shown on 26 October 2003. Selected
city names are in black; fire names in white (Westerling et al., 2004).