The German Indonesian Tsunami Early Warning System (GITEWS) is built upon a complex sensor data infrastructure. To best fulfill the demand for a long living system, the underlying software and hardware architecture of GITEWS must be prepared for future modifications both of single sensors and entire sensors systems. The foundation for a flexible integration and for stable interfaces is a result of following the paradigm of a Service Oriented Architecture (SOA). The Tsunami Service Bus (TSB) - our integration platform in GITEWS - realizes this SOA approach by implementing the Sensor Web Enablement (SWE) standards and services. This paper focuses on architectural and implementation aspects of the TSB. Initially, the general architectural approach in GITEWS by SOA and SWE is presented. Based on this conception, the concrete system architecture of GITEWS is introduced. The sensor integration platform TSB is then discussed in detail, following by its primary responsibilities and components. Special emphasis is laid on architectural transparency, comprehensible design decisions, and references to the applied technology.