**3. A Mexican tsunami early warning system**

As mentioned in previous sections, tsunamis (and earthquakes) are unpredictable and can happen any time. Therefore, there is a need for an effective tsunami early warning system (TEWS). A system which should include not only the technical aspect but also the human issue. This section presents a preliminary model for such a system.

In particular, it considers the Pacific and the Caribbean coasts of Mexico (Section 2). However, only those aspects associated with the "structural-organisation" of the proposed model will be discussed in some detail (i.e., the five interrelated subsystems associated with systems 1–5 and its channels of communication as shown in **Figure 6**). The proposed model is based on previous research on issues related to safety and disaster management systems [30–32].

In the context of this case study, the overall function of systems 2–5 (MTEW-SMU) is to establish the key tsunami safety policies aiming at maintaining tsunami risk within an acceptable range; this implies allocating the necessary resources, for example, to build response capabilities at national and community levels.

System 1, on the other hand, embraces the following three subsystems: TNZO (Tsunami Northern Zone Operations), TSZO (Tsunami Southern Zone Operations), and TCZO (Tsunami Caribbean Zone Operations) with their associated management units (TNZ-SMU, TSZ-SMU & TCZ-SMU). These three operations of system 1 were considered given the fact that the risk of tsunamis comes from local and remote tsunami sources as mentioned in Section 2.

Further, it is important to highlight that one of the key functions within the MTEW-SMU is that related to System 2, which is associated with what it is called here MTEW-CC (Mexican Tsunami Early Warning-Coordination Centre); its key function is the monitoring, detection of a tsunami through the following coordination centres: TSZ-CC (Tsunami Southern Zone-Coordination Centre), TNZ-CC (Tsunami Northern Zone Coordination Centre), and TCZ-CC (Tsunami Caribbean Zone Coordination Centre), as shown in **Figure 6**. The process of the flow of key information and decision making process is briefly described in **Table 3**; **Table 4**, on the other hand, presents some of the key actors involved in the existing system when compared with the features of the model.

In general, communities living in active seismic areas and along coastal regions are vulnerable to tsunamis. These natural hazards are not that common and unpredictable, but powerful and with devastating consequences to those communities in

#### **Figure 6.**

*A Mexican tsunami early warning system (MTEWS).*

their path. It is believed that tsunamis are the deadliest in terms of the proportion of people being killed [34].

Following the 2004 tsunami in the Indian Ocean, the need for a tsunami warning system (TWS) was more than evident; however, it may be argued that the existing TWS may be deficient in dealing with the mitigation of impacts of such events; moreover, there are still regions worldwide without such systems.

**201**

*The Risk of Tsunamis in Mexico*

**"Action points"**

"2&2A", "7&7A"

"3&4", "8&9", "13&14"

"4A", "9A", "14″

**Table 3.**

*DOI: http://dx.doi.org/10.5772/intechopen.94201*

**Description**

"action point" "7A".

necessary.

*Description of the key action points of the model in Figure 6.*

"1", "6", "11" Flow of data on key variables monitored by MTEW-CC through TNZ-CC, TSZ-CC,

PTWC (Pacific Tsunami Warning Centre), see **Table 4**.

decision-makers within this zone are on alert.

(i.e., TSZ-CC & TCZ-CC), see **Figure 6** and **Table 4**.

to "9A" and "14" within their respective coordination centres. "5", "6", "15″ "Action point" "5" issues the tsunami warning to the affected communities within this

zone (e.g. Acapulco, Oaxaca, Manzanillo, Zihuatanejo, etc.).

this zone (e.g. Cancun, etc.), see **Figure 6**.

TCZ-CC (e.g., earthquakes, pressure sensors, tide gauges, etc.). It should also be mentioned that this information is provided by the SSN (National Seismological Service), USGS, the

If a strong earthquake occurs, for example, within TNZO (Tsunami Northern Zone Operations), then in "2", the tsunami risk is assessed, if the key variable not withing the acceptable criteria (e.g., a tsunami), then it issues the tsunami warning to "2A", which in turn issues the warning to the TSZ-CC, even if the risk is low (Section 2), through the

In the model, the TCZ-CC also receives the warning, although in the context of this scenario, it is not necessary to warn communities within TCZO (Tsunami Caribbean Zone Operations) to take some protective actions for obvious reasons. Nevertheless, the key

"Actions points" "3&4" plan and devise measures to respond to the tsunami emergency, e.g., design of risk maps, plans to conduct drills, evacuation plans; etc. All of these aiming at better prepare the vulnerable communities within TNZO. "Action point" "3" also issues the tsunami warning to MTEW-SMU (i.e., to System 3). In the same vein, "action points" "8&9" and "13&14" perform similar functions into their respective coordination centres

Following the scenario herein, "4A" communicates the protective measures taken (e.g., evacuation) to the MTEW-CC, which in turn may devise further actions given its synergistic view of the total system through system 3, as shown in **Figure 6**. The same rationale applies

zone (e.g. B.C, B.C.S., Sinaloa, Manzanillo, etc.). Further, it implements all the protective measures to mitigate the impact of the tsunami in the coastal areas, e.g., evacuation to safe areas, etc. Moreover, it also implements plans to relocate the affected people to safe areas if

Similarly, as in "5", "6" issues the tsunami warning to the affected communities within this

"Action point" "15", issues the warning to the communities vulnerable to tsunamis within

Recent tsunami disasters have highlighted some of these deficiencies; for example, in the case of the 2010 tsunami in Chile, the entity in charge of issuing a tsunami warning failed to do so [5], p. 30 (see "action point" "2"& "7" in **Figure 6** and **Table 3**). The failure to perform this action contributed to fatalities in the coastal communities. More recently, the 28 September Sulawesi tsunami and the 24 December Anak Krakatau (AK) volcano tsunami, both in Indonesia, illustrate deficiencies in TWS too. In the former case, the tsunami warning was issued but the warning was lifted over thirty minutes [4]. However, the city of Palu, located in a narrow bay, was hit hard with waves reaching six metres of height; why were not they warned? the head of the BMKG (Indonesia Agency for Meteorology,

Climatology and Geophysics) argued that "we have no observation data at Palu…", "If we had a tide gauge or proper data in Palu, of course it would have been better" [4]. The tsunami (and earthquake) killed over 2000 people [2]. Finally, regarding the AK volcano tsunami, it is thought that there was not a tsunami warning system for the case of volcano-induced tsunamis; however, the tsunami killed 437 people [3]. It may be argued that a TWS should not be only concerned with the technical infrastructure systems (e.g., tidal gauge, network of buoys, etc.), but also the organisational and human components. Further, it may be argued that the most
